How does the wave function of free particle $\psi(x,t)=A\exp \{ i(kx-\omega t)\}$ satisfy normalisation condition?

Normalizing the solution to free particle Schrödinger equation


When would the proposed black hole at the centre of Milky Way gulp in our solar system?

What happens when the black hole at a galactic core eats the galaxy?


What is the definition of temperature, once and for all?

How is temperature defined, and measured?


Is the classification of particles into matter and anti-matter arbitrary?

Identification of particles and anti-particles


Why do we automatically assume that the velocity vector $\vec{v}$ and location vector $\vec{r}$ are independent?

Calculus of variations -- how does it make sense to vary the position and the velocity independently?


Examples of number theory showing up in physics


How do we know Dark Matter is non-baryonic?

Why isn't dark matter just ordinary matter?


Why are our planets in the solar system all on the same disc/plane/layer?

Why do all the planets of the solar system orbit in roughly the same 2D plane?


Any book which introduces physics historically?


Does the no-cloning theorem mean that 2 systems can't have the same state?

The Interpretation of $|\psi|^2$ and the No-Clone Theorem


Why does light change direction when it travels through glass?


How can a green laser be reflected as orange?


Flux of electric field through a closed surface with no charge inside?


Book on Noether theorem and classical field theory

What's a good book for an advanced undergraduate/early graduate student to learn about symmetry, conservation and Noether's theorems?


Light interference with light and other EM waves

Why does light in a room not form constructive and destructive interference patterns?


How does light speed up after coming out of a glass slab?


How does kinetic energy work in braking a vehicle?


Why does a $1/2$ appear in this simple capacitor equation?


How does static friction provide centripetal acceleration?


Why to use the sign convention while solving problems as the mirror-formula itself is derived using the sign convention?

Sign convention for mirror and lens formulas


How does GR determine the topology of spacetime?

What is known about the topological structure of spacetime?


Does the maximally-extended Schwarzschild horizon see the entire past of the parallel universe?

Does someone falling into a black hole see the end of the universe?


Non normalisability implies uncertainty principle?

is there any uncertainty on the free particle with a definite momentum $\vec p$?


Why the bob leaves the circular path when tension in the string becomes zero


How can you calculate the time it takes for an object to fall from a great distance, while taking for account the change in gravity?

Calculating gravity when taking into account the change of gravitational force


Why does the rope fly up from the nail against gravity?


How could live and neutral wires be specified in a circuit with alternating current?

Difference between live and neutral wires


Is a force acting on a freely falling body?

When objects fall along geodesic paths of curved space-time, why is there no force acting on them?


I don't see that general relativity is really needed for GPS to work correctly


Space is expanding but the space around me isn't

Why does space expansion not expand matter?


Why would spacetime curvature cause gravity?


Why divide surface area to volume for strength in living beings?

How can an an ant lift 50 times its own weight and pull 30 times its weight?


Can a very long screen display an object travelling faster than light?

Is it really possible to break the speed of light by flicking your wrist with a laser pointer?


Does voltage drop occur with zero load and zero resistance


How does friction act in rolling motion?

What is the cause of rolling friction? & why is it less than sliding friction?


Realtion of acceleration and deformation

Elongation in bar with unequal applied forces


Heavy ball drops after lighter ball, will the heavy ball catch up to lighter ball?

Why do two bodies of different masses fall at the same rate (in the absence of air resistance)?


Which is stronger, a rope without knots or a rope with knots?


Free falling of object with no air resistance


How does Newton's 2-prism experiment help to explain why light does not get dispersed into 7-colors in a parallel glass slab?

Can anyone explain to me why light is not dispersed into a spectrum through a parallel glass slide, but only through a prism?


Why doesn't the Gravitational Force causes body to fall towards orbital center moving with constant tangential speed?

Why doesn't the Moon fall onto the Earth?


Flying a toy helicopter inside an accelerating train


If the Big Bang theory suggests that the Universe is "expanding" then what is it expanding INTO?

If the universe is expanding, what is it expanding into?


Train crash: are these situations alike?


If an anti-matter singularity and a normal matter singularity, of equal masses, collided would we (outside the event horizon) see an explosion?

What happens when a "matter-black-hole" and an "anti-matter-black-hole" collide?


Divergence of $\frac{ \hat {\bf r}}{r^2} \equiv \frac{{\bf r}}{r^3}$, what is the 'paradox'?


When is energy converted to mass? What are the required conditions to do so?

What keeps mass from turning into energy?


What becomes of conservation of energy in many-worlds theories?

Wouldn't the thermodynamic cost of creating alternate universes make the Many Worlds interpretation implausible?


Proof of conservation of spacetime interval

Proving invariance of $ds^2$ from the invariance of the speed of light


What really causes light/photons to appear slower in media?


Electric field near a uniformly charged ring using gauss law

Electric field at a point on axis of uniformly charged ring using Gauss law


Is looking at an eclipse worse than looking at the sun?

Are dangerous rays emitted during Solar Eclipse?


Newton's third law, why does this body move?

Given Newton's third law, why are things capable of moving?


Prove that the Lagrangian Density $\mathscr{L}$, which generates a given set of Euler-Lagrange equations, is not unique

Does a four-divergence extra term in a Lagrangian density matter to the field equations?


How does one come up with the model of torque?

How was the torque-force relationship discovered


What is the physical meaning of a dot product and a cross product of vectors?

What is the physical significance of dot & cross product of vectors? Why is division not defined for vectors?


Why do galaxies collide? Reconciling dark energy and an expanding universe with the fact that some galaxies are on a collision course

How and why will the Milky Way collide with the Andromeda galaxy?


Andromeda is made of antimatter. Am I wrong? Why?

How would we tell antimatter galaxies apart?


Infinity problem: Why is gravity $g=0$ zero at the center of Earth if according to Newton gravity formula $g=GM/R^2$?


Is there a "high temperature" variant of 0 degrees Kelvin?

Why is there no absolute maximum temperature?


Place each foot on a scale: can you add the two to find your weight?


As a car turns around a circle, why does the force of static friction point towards the center of the circle

Why does friction play the role of centripetal force during the turning of a car?


Einstein's equation: good, intuitive introduction anywhere?


Why is the covariant derivative of the metric tensor zero?


frictional force is nonconservative force

What is the origin of non-conservative force?


The physical meaning of ${\rm Tr}()$ in quantum mechanics

What information does the trace of a matrix give?


Do the mediums decrease or increase the speed of light? (source to target)

What really causes light/photons to appear slower in media?


Meaning of parallel axis theorem: why is the moment of inertia minimum if the axis passes through the CM?


What formally means when physicists say "relativity theory is inconsistent with quantum theory"?

A list of inconveniences between quantum mechanics and (general) relativity?


Is there a "framerate" for the universe?


What is the meaning when we say something is at the higher potential and the other is at lower and wht is the direction of flow of charge?

Won't the test charge disturb the electric field to be measured?


Carroll's derivation of the geodesic equations

Geodesics equations via variational principle


Why is $|\Psi|^2$ the probability density?


Infinite energy with water and air balls

Why doesn't this perpetual motion machine using the buoyant force work?


Is the magnetic field calculated by Ampere's Law only because of the currents crossing the loop?


How does the "computer fan with magnets" generator "work"?


Highest temperature possible to achieve using magnifying glass and sunlight

Is it possible to focus the radiation from a black body to make something hotter than that black body?


Confused about voltage due to a point charge

Electric potential - different definitions


How does the kinetic energy of a ballerina increase?


How do subatomic particles have mass, velocity, spin etc if they are waves?

How can a red light photon be different from a blue light photon?


Black holes and positive/negative-energy particles


Why do earphone wires always get tangled up in pocket?


What proof do we have that space is expanding?

How do we know for certain that space is expanding?


Why can't weak interaction bind neutrino and electron together?

Can the weak force create a bound state?


Do the terms "damping constant" and "damping coefficient" have standard uses?


Is it possible in principle to determine the temperature and pressure of the gas when a piston is half-way through the compression?

What happens to the temperature when an ideal gas is compressed?


Why are our planets in the solar system all on the same disc/plane/layer?


Are transitions between stationary orbits part of the Bohr model?

Why don't electrons crash into the nuclei they "orbit"?


Why is angle of incidence equal to the angle of reflection?

Explain reflection laws at the atomic level


Excess charge on an insulator and conductor


Why does any charge flow through a parallel branch with a higher resistance?

Path of least resistance vs. short circuit


Hamilton-Jacobi equation and method of solving it

How to explain the different forms of the Hamilton-Jacobi equation?


Derivation of Hamilton-Jacobi theory using canonical transformations


Why are systems joined via a tensor product?

Tensor product vs. Cartesian Product for composite quantum systems


the asymptotic series of $\frac{1}{\gamma^{\mu} p_{\mu}-m_0 -\Sigma(p)}$

How can we use geometric series in calculating Green's function sum over loop effects


Distinguishing monochromatic light from light of a mixture of wavelengths, both of same colour

Why can we distinguish different pitches in a chord but not different hues of light?


What would a hydrogen balloon find easiest to lift?

Is a block of cotton heavier than a block of iron?


What's the difference between gravitational attraction and weight?

Is there a difference between Weight and Force of Gravity?


Why has there never been measured a free quark or gluon, but only objects that are built out of them, such as mesons and baryons?


Orthonormality and completeness in infinite dimensions: 2 different definitions

Normalization of basis vectors with a continuous index?


Why should the friction between two disks be zero when there velocity is same?

Does a tire need to slip to generate force?


Does mass slow down an object falling through the atmosphere?

Why do heavier objects fall faster in air?


Conservation of Energy for Uniform Circular Motion in a Vertical Plane

Vertical uniform circular motion.. can it really be uniform?


How is the behaviour of an atom particles as the atom approaches the speed of light?

What changes occur while an atom approches the speed of light?


What is the role of $\hbar$ in quantum mechanics?

Physical Interpretation of Planck's Constant


Gravitational field strength to distance graph


Black hole and lepton number conservation

No hair theorem for black holes and the baryon number


Problem in counting bonding pairs (elementary mean-field theory on the Ising Model)

Mean field theory formulation of Ising model


How can magnets be used to pick up pieces of metal when the force from a magnetic field does no work?


Lagrangian is there so why we need hamiltonian?

What's the point of Hamiltonian mechanics?


Does gravity have any effect on sound waves?


What is the carrier of push and pull force?

What does it mean for two objects to "touch"?


Calculating impact force for a falling object?


Are eigenfunctions always normed and orthogonal?

"An operator is hermitian". Implications?


How do we know that the dark matter is cold or non-relativistic?

Why do physicists think that the dark matter is cold?


Should these be called "weights" or "masses"?


If the universe has a fixed amount of mass, does it mean it has a fixed amount of energy or not? Because of the whole $E=mc^2$ thing?

Is the total energy of the universe zero?


How is the classical twin paradox resolved?


What exactly does the *frequency* of a photon mean?


How do I know what the symmetry group of a Lagrangian is?

Is there a systematic way to obtain all conserved quantities of a system?


Given redshift how do I obtain distance in parsec?


Expected result of vertical Michelson-Morley Experiment

A vertical variation of modern versions of Michelson-Morley


Can someone be too late for being a great physicist?

Is it possible to restart formal higher education in physics at a later age?


Is there a "magnetic gravitational" field?

Is the description of the gravitational field as a vector field and a tensor field compatible?


The nature of the gravity force: Is it attractive or repulsive between positive and negative mass?


Do COBE, WMAP, and Plack have design flaws?

Do oceans produce the cosmic microwave background?


How can a proton be converted to a neutron via positron emission and yet gain mass?


If you are ontop of a giant heavy object that is falling from the sky, is it possible to jump and roll at the perfect time to survive?

Would it help if you jump inside a free falling elevator?


Magnetic field resistance material: are there any?

Shielding magnetic field without mu-metal


Relationship between vector field, generator & scalar field in Noether's theorem

Noether's Theorem: Lie groups vs. Lie algebras; finite vs. infinitesimal symmetries


How to measure power used to sustain something in a (gravitational) field?

Why does holding something up cost energy while no work is being done?


Is there a maximum possible acceleration?


Thermal radiation spectrum of a blackbody


Why does my kettle only make a noise when it is turned on


Capacitance of bodies with different charge

Capacitor with different charges on each plate


Can Information Travel Faster Than The Speed Of Light?

Is it possible for information to be transmitted faster than light by using a rigid pole?


Is time dilation an illusion? Variation on the twins paradox


How occurs the enantiomorph of the mirror?

Why are mirror images flipped horizontally but not vertically?


A correct explanation for the levitation of a superconductor above a magnet

How does quantum trapping with diamagnets work?


What exactly is the "coherence" between waves?


Special Relativity - What is an intuitive way to think about time dilation?

Time dilation and twin paradox: If they twins were speaking on a phone of some kind, how would each other's voices sound?


Have sequential Stern Gerlach experiments been actually conducted or are they purely thought experiments?


Why is quantum mechanics based on probability theory?

How can we be sure that nature isn't "faking" quantum statistics?


Can the mass of an orbiting object and the object being orbited be determined by the distance and orbit velocity alone?

Does mass affect speed of orbit at a certain distance?


Can solar furnace achieve higher temperature than sun surface?

What temperature can you attain with a solar furnace?


Why Earth’s magnetic field is reversing its direction every few million years?


How could vacuum energy cause the expansion of the universe?


Are there (or could there be) electrically charged particles that move at the speed $c$?


Understanding weight on an inclined plane


Why do two bodies of different masses fall at the same rate (in the absence of air resistance)?


Do we know for sure that laws of physics are time invariant?


How does an electron absorb or emit light?


How to calculate temperature of an incandescent bulb filament?


Is there a hard upper bound to the deBroglie wavelength of a particle with vanishing momentum?

Validity of naively computing the de Broglie wavelength of a macroscopic object


What are the reasons to expect that gravity should be quantized?


Why does an accelerating neutral object not emit Bremsstrahlung radiation?

Do composite particles that are electrically neutral but have charged constituents radiate?


How general relativity gets to an inverse-square law

How can we recover the Newtonian gravitational potential from the metric of general relativity?


Correct terminology for combined kinematic and dynamic state

What is the difference between "kinematics" and "dynamics"?


How long must escape velocity be maintained?


How is the gravitational potential energy of an object different from that of a system?

Does the potential energy of a single object exist?


Action Reaction when I pushing a trolley?

Given Newton's third law, why are things capable of moving?


Classical Mechanics: Continuous or Discrete universe?


Lagrangian formalism and dissipative systems

Lagrangian and Hamiltonian EOM with dissipative force


Probability of photoelectric effect for gamma rays

Photoelectric effect absorption coefficient decreases with energy, why?


The electric field generated by a point charge becomes infinite when distance tends to zero. What physical meaning does this have?


Do black holes cause gravitational redshift?

If you shoot a light beam behind the event horizon of a black hole, what happens to the light?


Are energy and momentum separable for EM waves


Exeeding the speed of light by adding velocities

What is the relative speed of two near-light speed particles headed towards each other?


$E=mc^2$ what is unique about the speed of light?

What is so special about speed of light in vacuum?


What does a supercharge physically conserve?

What is the physical meaning of a Supercharge?


Can someone show me the chain of events which will lead to a faraway hurricane when I clap my hands (leaving everything else the same)?


How to rebut denials of the existence of photons?

Can the photoelectric effect be explained without photons?


Why is it that friction apparently decreases with speed?

Does the force of kinetic friction increase with the relative speed of the objects involved? If not, why not?


Can there be black light? I mean is it possible to devise a machine that outputs darkness?


Do eyeballs exhibit chromatic aberration?


What is the weight equation through general relativity?


Relative speed when approaching the speed of light


How come gravity is $\mathcal{N}=8$? Why is graviton spin 2

How can I read off the fact that gravity is associated with spin-2 particles from the Einstein-Hilbert action?


Consequences of inverse square law with vast distances (Gravity); (in addition, is light speed broken)?


Will this sail-based moving system work? Why?


Is it true that water go down the drain counterclockwise in the northern hemisphere and clockwise in the southern

How to show that the Coriolis effect is irrelevant for the whirl/vortex in the sink/bathtub?


What is the experimental uncertainty of an ensemble measurement?

Multiple measurements of the same quantity - combining uncertainties


How is it that Quantum entanglement does not let you transmit infomation?

The choice of measurement basis on one half of an entangled state affects the other half. Can this be used to communicate faster than light?


How can the momentum-position Uncertainty Principle not violate conservation of energy?

Energy conservation limited by uncertainty principle


Has the formation of a new quark pair as we separate two quarks been observed or is it only a prediction?

Has confinement been experimentally observed?


Did the derivation of self inductance equation overcalculate winding number?

Why do we multiply the magnetic flux by the winding number?


Is uncertainty in velocity via HUP reference frame dependent?

Is uncertainty principle a technical difficulty in measurement?


Can an electric field be detected around a large black hole?

Detection of the Electric Charge of a Black Hole


Question on kinematics and theory of relativity

If I run along the aisle of a bus traveling at (almost) the speed of light, can I travel faster than the speed of light?


Why doesn't the changing field of a moving charge create EM waves?

Magnetic field due to a charge having uniform velocity


Is the equipartition theorem derivable from more basic principles

For which systems is the equipartition theorem valid?


Why are the dineutron and diproton unbound?


Is expectation value of the Hamiltonian always the energy?

When is the Hamiltonian of a system not equal to its total energy?


Imagine I'm on a spacecraft that was accelerated to 1.0$c$ could I only move backwards?


What is the relation between temperature and electromagnetic radiation emitted by a body?

What are the various physical mechanisms for energy transfer to the photon during blackbody emission?


Physical motivation for Lagrangian formalism


Why do certain mesons not self-destruct?


Charged metal sphere- electric potential

Why is the conductor an equipotential surface in electrostatics?


What is the qualitative difference between quantum superpostion and mixed states?

How is quantum superposition different from mixed state?


Quantum mechanics - "God does not play dice" - does he? Or might he not?

Is the universe fundamentally deterministic?


Black holes and positive/negative-energy particles


Gaussian Minimizes Uncertainty - Statement Qualification

Minimum Uncertainty Wavefunction derivation


Is the age of the Universe relative to where you are within it?


What is the significance of the Inverse-square law?

Why are so many forces explainable using inverse squares when space is three dimensional?


Tricky operator identity: $[L^2,[L^2,\vec{r}]]=2 \hbar ^2 \{ L^2, \vec{r}\}$?


The mass-energy equivalence is a principle which can not be derived from anything?


Prove that an electron in a hydrogen atom doesn't emit radiation

Why don't electrons crash into the nuclei they "orbit"?


How can we look back at our Universe 13Billion years ago?

Looking out into the universe means looking back in time - how does that work?


How is the energy efficiency in bicycles accounted for?

What makes running so much less energy-efficient than bicycling?


Did Leggett and Caldeira solve the measurement problem?

Does measurement, quantum in particular, always increase the total entropy?


What is happening to energy that is not used as work?

Why does holding something up cost energy while no work is being done?


Experiment proving that the Earth is rotating around the Sun

What is the simplest way to prove that Earth orbits the Sun?


Why are dot products scalar, intuitively?

What is the physical significance of dot & cross product of vectors? Why is division not defined for vectors?


In what order should the subjects be studied in order to get to String Theory

What should a physics undergrad aspiring to be a string theorist learn before grad school?


Time dilation when falling into black hole

Does someone falling into a black hole see the end of the universe?


Capillary action and conservation of energy

When water climbs up a piece of paper, where is the energy coming from?


Sun is giving new energy everyday. Then how does this phrase make any sense: "Energy is never created nor destroyed, only transformed"?

If energy can neither be created nor be destroyed,what is the ultimate source of energy?


Why do galaxies over time become more refined?


Why is there a controversy on whether mass increases with speed?


How does electricity propagate in a conductor?


Contradiction to the law of conservation of energy while time travelling

Impossibility of time travel due to energy conservation?


Derivation of the Kubo formula in Ashcroft & Mermin

Derivation of Kubo Formula for Hall Conductance


Meaning of "phase delay" in forced oscillations

Phase difference of driving frequency and oscillating frequency


Why doesn't this perpetual motion machine using the buoyant force work?


Why the Lorentz group has complex generators in QFT treatments?

Is there a general theorem stating why the restricted Lorentz group's exponential map is surjective?


Is the vanishing of the covariant derivative of the metric necessary?

Why is the covariant derivative of the metric tensor zero?


Why don't cloud water droplets fall to the ground?


Good and Thorough Quantum Mechanics Textbook Recommendations

A book on quantum mechanics supported by the high-level mathematics


How is the CMB used to determine the age of the universe?

How has the age of the Universe been derived from the observations made by the Planck mission?


Why is the radius of the universe larger than?


Deriving different spin Lagrangian from one equation


Would a propeller attached to, but inside a sealed box work?

Will the box move if I blow air inside it?


Are window glasses transparent or opaque to infrared radiation?


If the universe is constantly expanding, shouldn't we go away from other planets?

Why does space expansion not expand matter?


How do we know that nuclear decay is truly random and spontaneous?

Is radioactive decay spontaneous or random?


Classical action as $S$-matrix generating functional at the tree-level

In what sense is the proper/effective action $\Gamma[\phi_c]$ a quantum-corrected classical action $S[\phi]$?


I am confused about the passage of time for an outside observer versus an observer moving at the speed of light

How long would it take me to travel to a distant star?


Don't heavier objects actually fall faster because they exert their own gravity?


How have we derived the definition of gravitational potential energy?

How has the definition of gravitational potential energy been derived?


Why do we remember the past but not the future?


Is it possible to detect a photon without intercepting it?

Can photons be detected without being absorbed?


Is there any case where one would use, snap, crackle or pop?

Is there any case in physics where the equations of motion depend on high time derivatives of the position?


Symmetry of the $3\times 3$ Cauchy Stress Tensor

Why is the (non-relativistic) stress tensor linear and symmetric?


Is Biot-Savart law obtained empirically or can it be derived?


Where to find cross section data for $e^{-}$ + $p$ $\longrightarrow$ $p$ + $e^{-}$?


Are holograms like in this video possible?

Is it (theoretically) physically possible to project an image into thin air?


Maxwell's equation in cylindrical coordinate system

Electromagnetic Tensor in Cylindrical Coordinates


Why does a ballerina speed up when she pulls in her arms?


Showing symmetry of the stress tensor by applying divergence theorem to $\int\int_{\delta V(t)} \vec{x}\times \vec{t} dS$


Why can we distinguish different pitches in a chord but not different hues of light?


Does entanglement not immediately contradict the theory of special relativity?

Why is quantum entanglement considered to be an active link between particles?


If inherent randomness exist in quantum mechanics, what then of eternalism implied by relativity?

How can a particle's position be random and uncertain in quantum mechanics if it is already pre-determined in relativity?


Geometric interpretation of Electromagnetism


Can total mechanical energy of an object, can be less than its kinetic energy?


Eigenvalues and eigenfunctions of the exponential potential $ V(x)=\exp(|x|) $


Was the choice of red/green colors for traffic lights a happy coincidence?


Possibility of making dark energy equivalent with dark matter


What happens with the force of gravity when the distance between two objects is 0?


Does this notation for the momentum in quantum mechanics make sense?

How does the momentum operator act on state kets?


Why is Heisenberg's uncertainty principle not an experimental error since it is the error created by photons striking on elementary particles?

Isn't the uncertainty principle just non-fundamental limitations in our current technology that could be removed in a more advanced civilization?


Conversion of mass to energy in chemical/nuclear reactions


Is it possible that there are more than 6 quark flavors/more than 3 generations?

Why do we think there are only three generations of fundamental particles?


will two entangled particles still remain entangled if one of the pair if sent inside of a black hole?

Can two particles remain entangled even if one is past the event horizon of a black hole?


When a photon escapes a black hole, why is it red shifted?

Have red shifted photons lost energy and where did it go?


Do neutrinos get their mass via interacting with the Higgs Boson?

Do neutrinos not couple to the Higgs field?


Distribution of Electric Charge on the surface of Sphere - simple explanation?

Why is surface charge distribution uniform for a conducting sphere? Can't it be arbitrary?


What would be the implications to physics if Newton was right about gravity?

How does Newtonian gravitation conflict with special relativity?


What is the relation between electromagnetic wave and photon?


Confusion regarding direction of electric field and dipole moment

Why does the direction of a dipole moment go from negative to positive charge?


Can rotating disk clocked at its center at the speed of light have an outer edge that travels faster than the speed of light?

Rotate a long bar in space and get close to (or even beyond) the speed of light $c$


Do small objects really exert a gravitional force?

Can the effects of a person's mass upon the local gravitational field be detected and measured remotely?


What is the reason gravitational waves propagate at speed of light?


Lagrangian density of a free electromagnetic field


Doubt about Lorentz transformations derivation

Interval preserving transformations are linear in special relativity


Is it better to use Lagrangian mechanics for all cases?

What is the difference between Newtonian and Lagrangian mechanics in a nutshell?


A conductor shaped like a square, what's the force between the two long wire segments?

Force between two finite parallel current carrying wires


Why do electrons move towards anode in the Photoelectric effect experiment?


Can you shine a laser on an object that has fallen into a black hole?

Does someone falling into a black hole see the end of the universe?


Pauli-Exclusion Principle, Why not a force?

Is Pauli-repulsion a "force" that is completely separate from the 4 fundamental forces?


Why does interference take place even though coherence is absent in YDSE

Is coherent light required for interference in Young's double slit experiment?


Is it possible that a person with myopia will see a blurry picture as normal?

Is it possible to blur an image in such way that a person with sight problems could see it sharp?


What is a qualitative description of energy?

What's the real fundamental definition of energy?


What happens to the energy when waves perfectly cancel each other?


Why doesn't a moving object spontaneously slow down and heat up?

Why can the entropy of an isolated system increase?


In what way does general relativity predict gravitational waves?

Gravitational wave solutions to the Einstein field equations


The minimal knowledge required for theoretical research in Quantum computing & AMO physics


Where do planets get energy to revolve around sun?

Why doesn't the Moon fall onto the Earth?


Why does my wife's skin buzz when she's using her laptop?


Using photons to explain electrostatic force

Deriving the Coulomb force equation from the idea of photon exchange?


What's so strange with this picture? Which optical phenomenon is working here?


Calculating a 2D collision between two perfectly circular disks

How to get the new direction of 2 disks colliding?


Why you need a graviton when you have the higgs boson?


How much work is done when pushing against a brick wall?

Why does holding something up cost energy while no work is being done?


Can silicon droplets bouncing on a vibrating surface be a model for Quantum Mechanics?

What are the similarities/differences between the behaviors of Quantum particles and bouncing droplets?


Does light change color on its way through a window?

What determines color -- wavelength or frequency?


Force and Torque Question on an isolated system


Why does an object with higher speed gain more (relativistic) mass?

Does the (relativistic) mass change? Why?


Notation for two variables with same dimensions

Square bracket notation for dimensions and units: usage and conventions


Is there a finite amount of mass in the universe?

What does it mean that the universe is "infinite"?


Single photon and double-slit experiment


Current electricity and static electricity


Does light induce an electric current in a conductor?


Slinky base does not immediately fall due to gravity


Kinetic energy when observer is moving and object is stationary

Kinetic energy with respect to different reference frames


Confusion With Index Notation in Field Theory

How come $\frac{\partial(\partial_{\beta}A_{\gamma})}{\partial(\partial_{\mu}A_{\nu})} = g_{\beta\mu}g_{\gamma\nu}$?


Physical sense of angular momentum conservation

If I push or hit an object in space will it rotate or move along a straight line?


If mass is invariant then why cant we travel faster than light?

If rest mass does not change with $v$ then why is infinite energy required to accelerate an object to the speed of light?


direction of friction between block and table

Direction of Friction on two stacked boxes


What is the reason behind the direction of field lines of positive and negative charge

Why is electric field lines away from (+) and toward (-)?


Simple pendulm motion for larger angular displacement?

Why does a simple pendulum or a spring-mass system show simple harmonic motion only for small amplitudes?


Difference between classical spin and quantum spin

What is spin as it relates to subatomic particles?


Is it possible for information to be transmitted faster than light by using a rigid pole?


Is heat a form of energy or mode of transferring energy like work?


How to define white color scientifically?

How much red, blue, and green does white light have?


If Newton's third law is true, why can we sink in sand?

Given Newton's third law, why are things capable of moving?


Why does space expansion not expand matter?


How are black hole masses calculated from gravitational waves?

How were the solar masses and distance of the GW150914 merger event calculated from the signal?


Non-zero electric field inside a conductor, when applying an large external field


Is a magnetic field just a moving charge?

How do moving charges produce magnetic fields?


Total Energy of the ISS orbiting the Earth

Why is the total energy of an orbiting system negative?


Black holes and positive/negative-energy particles


What is $\Delta t$ in the time-energy uncertainty principle?


Expansion of Universe: Spacetime metric and Topological Variations?

What is known about the topological structure of spacetime?


Static as opposed to Kinetic Friction in Rolling Motion


What does it mean 'the observer' in Quantum Physics?

What is an observer in quantum mechanics?


Does voltage drop occur with zero load and zero resistance


If I run along the aisle of a bus traveling at (almost) the speed of light, can I travel faster than the speed of light?


does space-time expansion affect on fundamental particle?

Why does space expansion not expand matter?


Could there be a star orbiting around a planet?


Would atmosphere of Jupiter blow up if I launched a atomic bomb there?


Can I measure a journey time < 100 years on a 100 light year voyage?

How long would it take me to travel to a distant star?


How did Planck arrive at the idea that energy is quantized?

How did Planck derive his formula $E=hf$?


Estimation of Equatorial Bulge of the Earth


Photoelectric effect and photons: what suggests a particle nature if we only measure resulting current?

Can the photoelectric effect be explained without photons?


Is it possible to derive curvature of spacetime from EFEs to create a computer simulation of the solar system?

Is there an algorithm for N body simulations in General Relativity


Book recommendation: Introduction to astrophysical hydrodynamics

Compressible gas dynamics in the context of astrophysics


Work done by gas on atmosphere and work done by atmosphere on gas

Work done by isothermal expansion from two different viewpoints


Why doesn't the potential energy of any object equal 0


Why We use Current in the Ohmic Heating Formula Instead of Voltage


Given a complete set of time and space-like geodesics plus knowledge of how these geodesics vary is this enough to determine the metric?

Given a set of curved geodesics in 2D space, is there a way to determine the geometrical shape of said space?


Work done by our body in Cycling and Walking

Which requires more energy: walking 1 km or cycling 1 km at the same speed?


Is the event horizon a fixed (static, stationary) region?


Can't we assign any other direction for instantaneous angular velocity except along the axis of rotation?


Question about wormholes with ends moving relative to one another


Does Coulomb's Law, with Gauss's Law, imply the existence of only three spatial dimensions?


How is $J^{PC}$ value experimentally determined for new types of particles?


How long does it take a magnet to lose its magnetization?

How long does a permanent magnet remain a magnet?


What is the difference between toughness and hardness?

Are hardness, strength and toughness of materials not the same thing in a way?


Why does sunset over a body of water cause a path of light stretching towards the horizon?


How are the two definitions of Canonical Transformations related/equivalent?


What is the entropy of the universe today?


What would happen to the human body if we went almost at the speed of light?

Would travelling at relativistic speeds have any impact on human biology?


Deriving Coulomb's law from quantum electrodynamics

Deriving the Coulomb force equation from the idea of photon exchange?


Explain how (or if) a box full of photons would weigh more due to massless photons


Why is the electric field zero inside a hollow conducting sphere?

Why is the field inside a hollow sphere zero?


Why the galaxies form 2D planes (or spiral-like) instead of 3D balls (or spherical-like)?


Why do like charges repel and opposite charges attract?

Why do same/opposite electric charges repel/attract each other, respectively?


Magnetic field due to long current carrying conductor at a point near its end

How to use Ampere's Law for a semi-infinite wire with current?


Helmholtz Free Energy vs Gibbs Free Energy in Landau Theory

In the Landau theory of phase transitions, is the order parameter a thermodynamic variable of state?


Has really general relativity only two degrees of freedom (as in the Maxwell theory)?

Counting degrees of freedom for gravitational waves as a gauge field


entropy change during irreversible heat loss


How does one find the Hamiltonian corresponding to a pendulum equation of motion?

How can one derive the Hamiltonian-function out of a differential equation of second order that describes the motion of a pendulum?


Does friction depend on the area of the surface?

Does the contact area affect friction forces?


Why direction of Ampere's Law follows right hand rule?

Which mathematical operation does the right hand rule for current come from?


Can I create a device which will create silence?

Is it possible to use "negative sound waves" to "cancel out" a sound to create silence?


Could the uncertainty principle theoretically be violated at 0 K?

Absolute zero and Heisenberg uncertainty principle


How to compute minimum shallowness of quantum well to have at least one bound state?

Why the statement "there exist at least one bound state for negative/attractive potential" doesn't hold for 3D case?


Are far objects really accelerating away at that huge rate?

Does the universe expansion theory take into account that light emitted by massive stars is red-shifted?


Is there variation in the speed of light?

GR. Einstein's 1911 Paper: On the Influence of Gravitation on the Propagation of Light


Why is frequency used in the formula of energy that was invented by Planck?


Is Einstein's formula $E=mc^2$ the same as the kinetic energy formula $\dfrac{1}{2} mv^2$?

$E=mc^2$ resembles non-relativistic kinetic energy formula $E_K = \frac{1}{2}mv^2$?


The derivation and formula to calculate Potential Energy seems quite confusing?


What if the light of a star is from past?

How many naked-eye stars have 'died' since they emitted the light we are seeing?


Why don't we see solar and lunar eclipses often?


What does string theory predict for the singularity inside a black hole?


Meaning of "time" related to existence of the universe

What does one second after big bang mean?


Would putting a magnifying glass on a solar panel be beneficial?

Are Fresnel lenses widely used for solar electricity? If not, why not?


What becomes the center of rotation when torque is applied?

Why does an unhinged body rotate about its centre of mass?


Why is the derivative of $\Psi$ continuous at $x=0$?


Why is work done defined the way it is? What's the intuition here?

Why does the amount of energy transferred depend on distance rather than time?


What is the electrostatic potential on the surface of a conducting body?

Why is the conductor an equipotential surface in electrostatics?


When a rotating body contracts what work causes the change in its rotational KE

What is happening to rotational kinetic energy when moment of inertia is changed?


If the lunar tides are stronger than solar tides, doesn't that imply the surface gravity of the moon is greater than the surface gravity of the sun?

Why is the Moon considered the major cause of tides, even though it is weaker than the Sun?


How do you arrive at the de-Broglie wavelength?

Where does de Broglie wavelength $\lambda=h/p$ for massive particles come from?


Why does a ball exert force on the ground straight downwards even when the ball is thrown to the ground at an angle?

Why does a surface always exert force normal to it?


Is the normal force a conservative force?


Physical reason of difference between normal force in a banked curve and an inclined plane.

Why is $R\cos{a} = mg$ in circular motion compared and not $R = mg\cos{a}$?


Why is the work done by someone pushing a cart not zero?

Why does holding something up cost energy while no work is being done?


What is the physical origin of group velocity dispersion?

Why do prisms work (why is refraction frequency dependent)?


How does the momentum operator act on state kets?


Does a photon in vacuum have a rest frame?


How much of a galaxy's mass is in stars?

What fraction of baryonic matter is in stars?


How does virtual particle become real particle in Hawking radiation?

Black holes and positive/negative-energy particles


Infinitesimal transformations for a relativistic particle


Calculating the age of the Universe at temperature 1 MeV

How does the Hubble parameter change with the age of the universe?


Why does time slow down when traveling at high speeds

What are the mechanics by which Time Dilation and Length Contraction occur?


Can I practically demonstrate Gravitational Time Dilation by spinning a wheel very fast?

Can a ultracentrifuge be used to test general relativity?


Question about time dilation and relativity

How is the classical twin paradox resolved?


If entropy of a closed system decreases by a certain amount, why does not the entropy of the surroundings increase by the same amount?

Is a world with constant/decreasing entropy theoretically impossible?


What is the maximum possible frequency and wavelength?


Light speed in vacuum over space and time

The vacuum light speed: Is it really constant, i.e., independent of location in space-time?


How can I explain what a kilogram is using Planck's constant?

What are the proposed realizations in the New SI for the kilogram, ampere, kelvin and mole?


Can two solids, a human and a wooden desk, using only human muscular power to close the distance, actually physically touch at the atomic level?

What does it mean for two objects to "touch"?


Describing a motion of gyroscope with gimbal


How to understand the process of the kinetic energy formula?

Why is velocity squared in kinetic energy?


Why does space expansion not expand matter?


How does a electron revolve in Rutherford's model?

Why don't electrons crash into the nuclei they "orbit"?


What are the mechanics by which Time Dilation and Length Contraction occur?


Why photon only have helicity other than spin?

Why does photon have only two possible eigenvalues of helicity?


Finding the moment of inertia of a lever

Moment of inertia of a cylinder about its base


Why is the decay of a neutral rho meson into two neutral pions forbidden?


Cluster of Black Holes around a Central Point


Is there any danger standing in front of a household microwave?

How does the grid on the microwave oven window prevent microwave radiation from coming out?


Is there a method to obtain a Lagrangian from the equations of motion?

How do I show that there exists variational/action principle for a given classical system?


Why do Magnetic North and South Poles never exist by themselves?

Must every magnetic configuration have a north and south pole?


Is the total energy of the universe zero?


Action principles and covariant equations


Lorentz transformation, non linear space transformations

Interval preserving transformations are linear in special relativity


Why gravitation does not have negative entropy?

Please clarify how entropy increases when matter gravitationally coalesces


The Existence of the $^1D$ term and the non-existence of the $^3D$ term?


How does gravitational attraction relate to weight?

Is there a difference between Weight and Force of Gravity?


What's the point of Hamiltonian mechanics?


Ball Rolling Down An Inclined Plane - Where does the torque come from?


What will happen if a helicopter flew still?

Why does the atmosphere rotate along with the earth?


Given Newton's third law, why are things capable of moving?


Sum of nucleus less than sum of neutrons & protons?


Scenario of Crossing the speed limit of our Universe

If I am travelling on a car at around 60 km/h, and I shine a light, does that mean that the light is travelling faster than the speed of light?


If the Big Bang started in a state of low entropy then shouldn't the Big Crunch be in a state of low entropy also?


Why do electrons appear more frequently than it's counterpart, positrons?


Explanation of charge for a student just entering physics


Can the Particle nature of light be explained by wave interactions?


Generalized Pauli matrix for spin larger than 1/2

$t_1$, $t_2$, $t_3$ Hermitian generators of $SU(2)$


If Earth spun faster, would I be able to jump higher?

How would gravity change on a planet rotating around itself very fast?


what is the life span of permanent magnet and how does it reduces?

How long does a permanent magnet remain a magnet?


Heisenberg Uncertainty principle defined as $\Delta x \Delta p_x \geq h$ versus $\Delta x \Delta p_x \geq \hbar/2$

Factor 2 in Heisenberg Uncertainty Principle: Which formula is correct?


"Before" the Big Bang was the Universe really compressed into a mathematical point?


Simple proof of oscillation/nodal theorem in quantum mechanics

When does the $n$th bound state of a 1D quantum potential have $n$ maxima/minima?


A fundamental question about charge and speed of a particle


What happens when a charge spins at near- $c$?

What would happen if a charge could travel at $c$?


Why does an accelerated charged particle emit electromagnetic waves?

How and why do accelerating charges radiate electromagnetic radiation?


How many physical quantities could be computed in a generic Quantum Field Theory?

Is the S-Matrix the only quantum field observable?


Why did the liquid disappear from some unopened aluminum cans? My experience (read below) has not been answered

Why did the liquid seemingly disappear from some unopened aluminum cans?


Does a standalone neutron have temperature?

Can a single molecule have a temperature?


Why do bits of paper stick to the CRT television screen?


What is the irreducible set of fundamental principles of Special Relativity?

What axiomatizations exist for special relativity?


Can vector components be in turn decomposed?

Why taking components of a component of a vector is invalid?


I want to know about the quantization of mass


Does a black hole ever fully form to an outside observer?

Black hole formation as seen by a distant observer


What is the location of point charge with respect to the original charged body?


What causes atoms to have their specific colors?


What started the magnetic field of Earth

What is the source of Earth's magnetic field?


Newton's 2nd law for rotation (accelerated rolling and inertial frame of reference)

Why is the center of mass frame always used in rigid body dynamics?


Is it possible that dark-matter is composed of a large number of neutrinos from the big bang?

How do we know Dark Matter isn't simply Neutrinos?


When light reflects from a medium of lower index of reflection to a medium of higher index of refraction, why does the light undergo a phase shift?

Phase shift of 180 degrees of transversal wave on reflection from denser medium


Relationship between impact crater properties and kinetic energy?

Proportionality constant in crater equations


Reciprocal Time Dilation in Special Relativity


Spontaneous symmetry breaking of a spinor / vector field

Why cannot fermions have non-zero vacuum expectation value?


Interpreting $Q_i=\partial_{\nu}T^{i \nu}$ from dust

Physical interpretation of $Q^i = \partial _\nu T^{i \nu}$


Is it possible for a particle to orbit a singularity inside the event horizon

Do particles in a black hole stay in constant orbit?


Would you be weightless at the center of the Earth?


What will happen to a man if he hangs from the power cable of train using one hand and secondly using two hands?

Birds sitting on electric wires: potential difference between the legs


How can alpha or beta emission maintain equal numbers of protons and electrons?

Why does an atom remain uncharged after emission of an alpha particle?


What's the difference between hypothesis, theory and law?


Approximating magnetic field at center of current loop by solenoid of 1 turn

Why is the B field of a solenoid equal to $\mu_0 i n$ while that of a loop is $\frac{\mu_0 i R^2}{2(R^2+z^2)^{3/2}}$?


Is this video's notion of general relativity correct?

What does it mean for objects to follow the curvature of space?


Is it possible to dumb down the idea that "Time didn't exist until the big bang"?


Interval preserving transformations are linear in special relativity


What is the electric charge of the Sun and its corona?


What is time, does it flow, and if so what defines its direction?


Could I pick up a human with a strong enough magnet?

How strong of magnetic field would noticibly attract a person?


if force acts on a wheel away from the centre does it have both translatory and rotatory motion?


How to calculate $\langle 1/r^2 \rangle$ for hydrogen using Hellmann-Feynmann Theorem? Wikipedia is wrong, isn't it?

What are independent parameters in Hellmann–Feynman theorem?


Is it possible to simulate human behavior even with the existence of quantum mechanics?

Could the randomness of quantum mechanics be the result of unseen factors?


Deriving Conservation of Angular Momentum from Newton's Laws

Why is conservation of angular momentum considered a law?


Is it possible for information to be transmitted faster than light by using a rigid pole?


'Modern' Introduction to or Summary of SUSY and BSM?


What shape has the highest drag coefficient?


Why do we test electric fields with positive charges and not negative ones?


Why are extra timelike dimensions seldom considered?

Has the concept of non-integer $(n+m)$-dimensional spacetime ever been investigated by theoretical physicists?


Why does a rocket engine have increasing power as the speed of the rocket increases?

Why is the work done by a rocket engine greater at higher speeds?


Why does a shuttlecock flip head down even when dropped head up?

Why do archery arrows tilt downwards in their descent?


How do symmetries of nature give rise to the conservation laws?

Can Noether's theorem be understood intuitively?


Two-point correlation function in Peskin's book


Why is Higgs particle detected much later than top quark when it's lighter?

Why did it take so long to find the Higgs?


Finding the Symmetries of Action/Lagrangian

How to find the continuous transformations which leave the action invariant?


Check whether the expression shows periodic motion or simple harmonic motion


What slows down time relative to an observer: super gravity or super speed?

Is gravitational time dilation different from other forms of time dilation?


Why does the mass of a proton not equal the mass of its corresponding quarks?

Quarks in a hadron: where does the mass come from?


Explanation of why doesn't heat flow spontaneously from a colder to a hotter body

How do you prove the second law of thermodynamics from statistical mechanics?


Is speed of gravitational waves constant?


Sign of Lagrangian and stress-energy tensor for relativistic dust

Does metric signature affect the stress energy tensor?


Does orbital refer to a locus where the probability of finding an electron is maximum?


What is the difference between poisitive and negative charge?

Why is the charge naming convention wrong?


Open source computer algebra systems for general relativity


Confused about the definition of holonomic constraints

Holonomic constraints and degrees of freedom


Contradiction in my Lagrangian mechanics problem

How can you solve this "paradox"? Central potential


Why does lateral force act on front wheels when rear wheels are locked?

Why does locking the rear tires on a vehicle cause it to spin?


Is the Heisenberg uncertainty principle based on experimental imprecision in measurement?

Isn't the uncertainty principle just non-fundamental limitations in our current technology that could be removed in a more advanced civilization?


How long would it take for the solar core to destroy Earth?

How would normal matter behave under conditions found in the core of the sun?


Divergence of Electric Field Due to a Point Charge

Divergence of $\frac{ \hat {\bf r}}{r^2} \equiv \frac{{\bf r}}{r^3}$, what is the 'paradox'?


Reflection and absorption of light at atomic level?

Explain reflection laws at the atomic level


How do black holes lose mass by hawking radiation?


Confusion regarding depiction of Electromagnetic Waves

Understanding the diagrams of electromagnetic waves


Sign of the vector (especially $g$) while calculating


How does Force translate a body if each molecule if pulled with a force,pulls the next molecule and still the body moves?

Given Newton's third law, why are things capable of moving?


Can I morph dimensionful physical constants meaningfully?

Is it possible to speak about changes in a physical constant which is not dimensionless?


Can an oscillating ordinary stone produce an electromagnetic wave?

Do composite particles that are electrically neutral but have charged constituents radiate?


What is the escape velocity in the Kerr metric?

Escape velocity from a rotating black hole


Electroweak symmetry breaking and mass generation

What is the relation between the Higgs field and chirality?


Can the velocity of the center of mass of two spheres change after a collision?


What is the speed of light escaping a neutron star?

Speed of light in a gravitational field?


Equivalence of two definitions of the stress-energy tensor in general relativity


Would you weight more on the equator or pole of an ellipsoid?

Why is Earth's gravity stronger at the poles?


What is the maximum possible frequency and wavelength?


How does the tension in the clamp of a atwood machine equal twice the tension in the string?


What are the consequences of LHC results for supersymmetry?

Which SUSY models are affected by the recent LHCb result?


dimensional analysis - how to find the dimensions of a variable inside an angle


Why is velocity squared in kinetic energy?

How can kinetic energy be proportional to the square of velocity, when velocity is relative?


Special Relativity: Time dilation paradox

Explanation for a much simpler version of the twin paradox?


When frictional force is always acting on rear wheel of cycle how maintaing of constant speed is possible?(neglect drag)

If friction acts on car all time, why is it not accelerating forever?


$P=F/A$ and $P=\rho*g*h$ give different answers


Why can't voltage in a capacitor change instantaneously?

Why is the voltage across a capacitor and the current across an inductor continuous?


Why Hawking radiation emission rate inversely proportional to black hole mass?

Why is the intensity of Hawking radiation dependent on the size of the black hole it comes from?


Mathematical Reasoning for Fluid Pressure as a Scalar


What wilI I observe when travelling at almost the speed of light?

Would time freeze if you could travel at the speed of light?


Recommend books on mechanics, motion and it's laws

Recommendations for good Newtonian mechanics and kinematics books


Relationship between $\star$-products in phase-space QM and NC geometry

Moyal Product in Non Commutative Quantum Mechanics


How to find distance travelled when the change in the force of gravity is not negligible?

Integrating radial free fall in Newtonian gravity


Discrete vs Continuous spectra of operators

Why are eigenfunctions which correspond to discrete/continuous eigenvalue spectra guaranteed to be normalizable/non-normalizable?


Question about electric flux in the corner of a cube


In beta plus decay proton gets converted to neutron-- where does the extra mass come from?


Is 3+1 spacetime as privileged as is claimed?


How will Andromeda collide with Milky Way in spite of Hubble's law?

How and why will the Milky Way collide with the Andromeda galaxy?


Why does air feel cooler when blown through a small hole and warm through a big one? (for example from a mouth)

Why does the air we blow/exhale out from our mouths change from hot to cold depending on the size of the opening we make with our mouth?


Is not length contraction a distortion of light?


Why maxwells speed distribution law doesn’t violet special theory if relativity

Is there a relativistic generalization of the Maxwell-Boltzmann velocity distribution?


Time dilation as an observer in special relativity


Inexact measurement and wavefunction collapse


Is there such a thing as "Action at a distance"?


Can we hear on Mercury, since the atmosphere is so thin?

What is the minimum pressure of a medium for which a sound wave can exist?


Are Newton's "laws" of motion laws or definitions of force and mass?


Can the shape of our Universe be a Mobius strip?


How many tensor product terms are necessary to express a separable state?

What is the minimum number of separable pure states needed to decompose arbitrary separable states?


Frequencies of a standing EM wave in a box (Schwartz QFT)


Will the volt, ampere, ohm or other electrical units change on May 20th, 2019?

What are the proposed realizations in the New SI for the kilogram, ampere, kelvin and mole?


Schrodinger equation: If $V(x)=V(-x)$ then prove that $\psi(x)=\psi(-x) $ or $\psi(x)=-\psi(-x)$

Time-independent Schrödinger function: If the potential $V$ is even, then the wave function $\psi$ can always be taken to be either even or odd


In Newton's gravity, is the inverse square law related to the fact that our Universe has (apparently) 3 dimensions?

Inverse Square Law and extra space dimensions


Why does going close to absolute zero take out friction?


Why don't we consider centrifugal force on a mass placed on earth?


Define Pressure at A point. Why is it a Scalar?


What does multiplying two real-world values represent?

What do units like joule * seconds imply?


Vertical Circular motion - Tension and velocity


Would it take more, or less than twice the force to inflate a balloon to a radius twice as big?

Relationship between balloon size and pressure


Why will the number of neutron higher than the number of proton in the most of atom?

Stable Nuclei - Deviation from equal protons and neutrons


Difference between gravity and a flat earth moving up

Is the lay explanation of the equivalence principle wrong?


What is special about quantum entanglement?

Quantum entanglement vs classical analogy


Definition of mass in agreement with relativity

Why is there a controversy on whether mass increases with speed?


Could one or more black holes be used to pull something out of another black hole?

Is it possible for one black hole to pull an object out of another black hole?


Do light particles come in different sizes?

How is wavelength actually related to space (/distance)?


Closed Room Experiment to prove Earth isn't flat

What is the simplest way to prove the Earth is round?


Is it really possible to break the speed of light by flicking your wrist with a laser pointer?


Why do the big nuts always remain at top? The Brazil-nut Effect


How are unbalanced forces even possible, given Newton's 3rd law?

Given Newton's third law, why are things capable of moving?


Capacity of an orbital to hold muons and electrons


How can it be that the sun emits more than a black body?


Does Quantum Mechanics say that anything is possible?

Is it true that quantum mechanics technically allows anything to happen?


Is there a standard of rest in the universe?

Is the CMB rest frame special? Where does it come from?


Why do my fingertips spark when rubbing a blanket?

Why does rubbing feet against sheets create a spark?


Why does splitting hot tea from one glass in two glasses makes it cool faster?


If we attach a fan at the end of a boat and switch it on, will the boat move?


Is Hawking radiation valid for a microscopic black hole?


Change in acceleration due to gravity because of rotation of earth

Constant of gravity in earth fixed coordinate system


Getting an object to travel at or near light speed by adding velocities

If I run along the aisle of a bus traveling at (almost) the speed of light, can I travel faster than the speed of light?


If I point a torch up, would the photons hit anything?


Why Is Newton's second law $F=ma$, and how did Newton "Discover it"?


Which of the two definitions of mass is the correct?

What's the difference between the five masses: inertial mass, gravitational mass, rest mass, invariant mass and relativistic mass?


How can we show Power = $\mathbf{F}\cdot \mathbf{v}$?

What does the equation $P=\vec{F}\cdot \vec{v}$ really mean?


Is escape velocity really a velocity (rather than a speed)?


The least count of a stop watch is 0.1s. The time of 20 oscillations of the pendulum is found to be 20s. The percentage error in the time period is?

Has my textbook given the incorrect equation for calculating uncertainty in multiplication?


Why wouldn't a balloon suspended in an accelerating truck not move?

Why does a helium filled balloon move forward in a car when the car is accelerating?


What is the most recent date that can be measured using carbon-14 dating?

How do we know that radioactive decay rates are constant over billions of years?


Why is carbon dating limit only 40,000 years?


How do re-used plastic bottles acting as converging nozzles create a DIY air conditioner?

How does the Eco-Cooler air conditioner really work?


What is the physical significance of the imaginary part when plane waves are represented as $e^{i(kx-\omega t)}$?


Why does photon emit a frequency when its rest mass is zero?

Is $E^2=(mc^2)^2+(pc)^2$ correct, or is $E=mc^2$ the correct one?


What's the relationship between classical gravitational waves and gravitons?


Quantization of Angular momentum with Bohr model versus solving the Schrödinger equation


Why does photon have to travel in sideways to hit the light clock?


What is the smallest particle? What is the building block of an electron?


The magnetic moment of a particle (and a neutrino)


Why is there an upper energy limit on the photoelectric effect?

Photoelectric effect absorption coefficient decreases with energy, why?


A bee inside a car - An application of Newton's laws


Why does the wave-particle duality become unnoticeable with more mass?

Validity of naively computing the de Broglie wavelength of a macroscopic object


Energy efficiency: better to heat hot tub constantly or twice a day for a longer period?

Should I heat my room when I'm not here, energy-efficiently speaking?


Why does a perpendicular force not change speed?


Why can't using 2 separate measuring instruments to measure position and velocity work?

Uncertainty principle and multiple observers


From where does a photon get energy to speed up when it travels from an optically rarer medium to a denser medium?

How does light speed up after coming out of a glass slab?


What is a good book/lecture notes that covers Lagrangian and Hamiltonian mechanics and includes a lot of numerical computation?


application of Ampere's circuital law for finite thin straight current carrying conductor

Ampere's circuital law for finite current carrying wire


Why quasistatic doesn't imply reversible process?

Is there a quasistatic process that is not reversible?


Difference between kinetic energy and force

What is the relationship between force and kinetic energy?


Why should field operators satisfy the classical equations of motion?


What happens to energy when waves cancel out?

Why do travelling waves continue after amplitude sum = 0?


What are the similarities/differences between the behaviors of Quantum particles and bouncing droplets?

Bell's theorem and fluid-mechanical experiments using droplets: are local hidden-variable theories possible after all?


Nuclear Energy is measured in MeV, why not in Joules?


A drone, or any lifting vehicle, enclosed in a container. Will it lift along with the container?

A flying fly inside a sealed box on a scale


Width of depletion region in P-N junction


Why are second order PDEs so ubiquitous in physics?

Why are differential equations for fields in physics of order two?


Can Space-Time be Distorted by Anything Other Than Mass?


What is the source of the electric charge on the electron?


Would a mini-blackhole collision with Earth cause heating?

What would the effect be of a small black hole colliding with the earth?


Does modern physics have any explanation for what causes inertia?


How do electrons know which path to take in a circuit?


Time needed for a meteorite to reach the Earth surface

The Time That 2 Masses Will Collide Due To Newtonian Gravity


Why doesn't the equipartion theorem apply for a gas of diatomic molecules?

In counting degrees of freedom of a linear molecule, why is rotation about the axis not counted?


Nature of the electric field of a photon

What is the relation between electromagnetic wave and photon?


How can an electron behave as a wave and particles at the same time?

Is the wave-particle duality a real duality?


Why do universal constants have the values they do?


Impact of a 5th fundamental force discovery

Is the "protophobic fifth force" observed in nuclear decays a new fundamental force?


Does dark matter / dark energy could be simply regular mattter

Why isn't dark matter just ordinary matter?


Given Newton's third law, why are things capable of moving?


If there is a super massive black hole at the center of our galaxy then why is the center of our galaxy so bright?

Why don't the black holes appear black in color in images of galaxies taken from HST?


Can a human sized object vibrate so fast it appears invisible to the human eye?

Can a human size object move so fast that it ceases to be observable?


Would a black hole evaporate before reaching the event horizon?

Does any particle ever reach any singularity inside the black hole?


Difference in symmetries of Second quantized and First quantized Hamiltonian

Why particle hole symmetry and chiral symmetry are called symmetries?


Are galaxies merely groups of nearby stars that collected together, or do the stars share a common birth?

Structure formation: Galaxies as different entities and stars as groups


Does the Sun revolve around the supermassive black hole at the center of the Milky Way?

Is sun revolving around certain mass in space with reference to some other galaxy?


Basics need to study quantum field theory after graduation?


Symmetrical twin paradox in a closed universe


Tips on basic electricity and magnetism books

Recommended books for advanced undergraduate electrodynamics


Light clock with mirrors on a moving train


What is the significance of angular frequency $\omega$ with regards to wave functions?


How does the number of photons hitting relate to the amplitude of a photon bundle/classical wave?

How is the amplitude of light related to number of photons?


Diagonal force of object on ramp: incorrect ratios?

Which is the correct triangle to draw to derive the force component along a rope?


Would time freeze if you could travel at the speed of light?


What is the latest definition of energy?

What's the real fundamental definition of energy?


Can relative velocity of a particle exceed the speed of light?

What is the relative speed of two near-light speed particles headed towards each other?


Why does lightning generate multiple branches?


Conditions for Static Equilibrium of Rigid Body

Is the moment of a force the same about any point?


Euler-Lagrange Equation Proving Maxwell Equation

Deriving Lagrangian density for electromagnetic field


Why is the absolute gradient of the metric tensor $\nabla_{\alpha} g_{\mu \nu} = 0$ in every coordinate system?

Is there a way to see that $ \nabla_\mu g_{\nu \rho} = 0 $ without explicit computation, where $\nabla_\mu$ refers to the covariant derivative?


Why use vectors to describe velocity/force/etc instead of treating magnitude and direction as separate values?


Is time really a 1-dimensional object that we only traverse through?

Intuition for multiple temporal dimensions


Derivation of some basic properties of conformal transformations

Topological/Geometrical justification for $\text{CFT}_2$ being special


Why doesn't an observer at rest on the Earth see Unruh radiation?

Do all massive bodies emit Hawking or Unruh radiation?


Is there oscillating charge in a hydrogen atom?


For the case where universe is not flat, has it got an extrinsic curvature towards (an)other spatial dimension(s)?

How could we know that the relativistic curvature of universe is intrinsic?


With relativity, what does the age of the universe *mean*?


Moment of inertia of a hollow sphere wrt the centre?


What is interaction and measurement in QM?

What is the difference between a measurement and any other interaction in quantum mechanics?


What is the added value of the lagrangian?

Advantages of Lagrangian Mechanics over Newtonian Mechanics


Gibbs free energy and it's physical significance


Why capacitor pass AC and block DC current?


What happens if light/particles exceeded the speed of light for a particular medium?


Why doesn't the frequency of light change during refraction?


Is rolling friction different from static friction?


Collisions of atoms in a gas and decoherence of wavefunctions

Is the wavefunction of particles inside a gas spread or localized?


The mystery behind the self-siphoning beads


How do enzymes use quantum tunneling (also, please use relatively simple vocabulary)?

How are our enzymes able to perform quantum tunnelling?


Why do we use radio waves for communication when gamma rays are more powerful?

Why we don't use gamma rays, x-rays or ultraviolet to transmit data?


If light is an electric and magnetic field how can it be absorbed(dont mark as duplicate)?

If light is an electric and (magnetic field), how can it be absorbed?


If refraction slows down light, isn't it possible to hold light still?


Can I model objects as point masses when calculating rotational inertia?

Is the solution to a question regarding four smaller masses on a rotating hollow sphere accurate?


What's wrong with this argument that kinetic energy goes as $v$ rather than $v^2$?

Why does kinetic energy increase quadratically, not linearly, with speed?


$F=ma$ calculation taking relativity into account?


The velocity of body and the increase in relativistic mass

Would travelling at relativistic speeds have any impact on human biology?


Will water waves diffract through a gap smaller than their wavelength?

What happens to waves when they hit smaller apertures than their wavelenghts?


Why action and reaction forces are not equal while walking on water?

Why can't we stand on fluid surface if newton's third law is applicable


Proof that the Hamiltonian is equivalent to energy when it is time independent

When does Hamiltonian equals to energy of the system?


Is there a formal definition of what a significant figure really is?


Is the notion of Lebesgue Measure a necessary construct for statistical physics?

When is Lebesgue integration useful over Riemann integration in physics?


Ambiguities in the energy-momentum tensor


If you exert force on a charge, doesn't it violate the conservation of energy?

How is the energy loss by an accelerating charge expressed in the equations of motion?


To What Extent are Magnetism and Gravity Related and Unrelated?

Noticing that Newtonian gravity and electrostatics are equivalent, is there also a relationship between the general relativity and electrodynamics?


Is Carnot engine the only reversible engine?

Must a reversible engine be a carnot engine?


When does a singularity start to exist during a black hole formation?


Why are $W$ bosons massless above electroweak scale?

Are there massless bosons at scales above electroweak scale?


Why is pressure over the wing lesser than the pressure on the bottom?


How exactly do protons and electrons interact with each other?


What is the difference between classical thermodynamics and statistical mechanics?

What is the difference between thermodynamics and statistical mechanics?


Rayleigh-Jeans Law difference between the frequency and wavelength forms


A query regarding constant $\frac{1}{4\pi \epsilon_{0}}$ in Coulomb's Law

Physical dimensions for the Coulomb force in SI and CGS


Lagrangian for relativistic massless point particle


An accelerated charge produces an electromagnetic wave. Is light an electromagnetic wave despite not having charged particles?

Why is light called an 'electromagnetic wave' if it's neither electric nor magnetic?


The difference between heat and temperature


Weird phenomenon on aluminum laptop casing

Why does my wife's skin buzz when she's using her laptop?


How can blackbody radition be explained by quantization?


Validity of naively computing the de Broglie wavelength of a macroscopic object


How is the uncertainty principle related to the non-commutativity of the multiplication of operators in quantum mechanics?

How does non-commutativity lead to uncertainty?


How particles can be found in classically forbidden regions?

Can a particle be physically observed inside a quantum barrier?


How to prove that both $\mu_0$ and $\epsilon_0$ don't depend on any frame of references?

Experiment measuring vacuum permittivity and permeability in high speed


Is the Uncertainty Principle a mathematical consequence or a physical consequence or both?

Is the uncertainty principle a property of elementary particles or a result of our measurement tools?


Is there a limit to the resolving power of a mirror telescope?


Is there an algorithm for N body simulations in General Relativity

$N$-body simulation in General Relativity


Is there a fundamental relationship between Coulomb's law and Newton's Law of Gravitation?

Noticing that Newtonian gravity and electrostatics are equivalent, is there also a relationship between the general relativity and electrodynamics?


Is there any matter inside an event horison?

Can matter really fall through an event horizon?


Why bumble bee cannot fly aerodynamically?

Is it really impossible for Bumblebees to fly?


Validity of gauge fixing in classical electrodynamics

Are gauge choices in electrodynamics really always possible?


Why does holding an object cost energy while no work is being done?

Why does holding something up cost energy while no work is being done?


Solar activity and radioactive decay rates

Strange modulation of radioactive decay rates with solar activity


Einsteins theory of relativity and formula of kinetic energy

$E=mc^2$ resembles non-relativistic kinetic energy formula $E_K = \frac{1}{2}mv^2$?


What is the difference and/or similarity between multiple universes in inflation and in quantumphysics?

Are many-worlds and the multiverse really the same thing?


When can the constant of proportionality in an eq be set equal to 1 and when not?

How do we know that $F = ma$, not $F = k \cdot ma$


What is the speed of transferring of energy in an inelastic solid?

Is it possible for information to be transmitted faster than light by using a rigid pole?


Why Nitrogen is still (almost) 3 times as abundant as Oxygen in Troposphere?

Why doesn't the percentage of oxygen in Earth's atmosphere diminish significantly with altitude?


Why doesn't pulling in your arms on a rotating stool violate conservation of energy?


What does the "moment" in the moment of force or the moment of inertia refer to?


Why we can use partial derivatives to tell if a force is conservative?

Why should Conservative forces have their curl equal to zero?(intuition)


Why can't capillary tubes overflow due to this reason?

How is the water meniscus at the edge of a capillary tube?


Does entropy always increase with temperature?

Do the number of possible microstates increase as temperature decreases?


Question about the Lehmann-Kallen representation in Srednicki

Why does the branch cut of the self-energy begin at $2m$?


Why doesn't orbital body keep going faster and faster?

Why doesn't an orbiting body keep accelerating?


Why probability of detection of optimum unambiguous discrimination between linearly independent symmetric states is less than random guess?

Why probability of detection by performing unambiguous quantum measurement is less than random guess in mesoscopic quantum regime?


Why a bullet leaves a hole on glass where stone makes scratch?

Can a bullet shot through a glass make a clean hole?


Is $E=mc^2$ strictly just a conversion formula?

Einstein equation $E=mc^2$: Does it mean an object without mass does not have energy?


Do strong and weak interactions have classical force fields as their limits?


Can glueballs, consisting of massles gluons, get a mass without reference to a Higgs field?

Glueball mass in non-abelian Yang Mills theory


About the steps in a book about Quantum Field Theory

Does $\langle\Omega|\mathrm{e}^{\mathrm{i}Px}=\langle\Omega|\mathrm{e}^{\mathrm{i}0x}$? $(\langle\Omega| =$ ground state of the interacting theory)


Where does the energy vanish in wave interference?

What happens to the energy when waves perfectly cancel each other?


How did people get ellipses of Newton's equations of motion and gravitation?

How is the equation of motion on an ellipse derived?


Why do animations of Stern Gerlach show the tiny magnets in fixed orientation?

Why does the Stern–Gerlach quantum spin experiment conflict with classical mechanics?


What stops water from a moon pool from filling the inside of a submarine?


What is the meaning of the shapes of various orbitals of the atom?

How can orbitals be oriented if the nucleus is symmetrical?


What is the relation between electromagnetic wave and photon?


Why doesn't a lighter flame cast a shadow?


Why is a Coulomb not a fundamental unit?

Why is the ampere a base unit and not the coulomb?


Is energy content of a system different depending on the observer?


Loop-Quantum Gravity versus String Theory


Definition of effective potential energy in two-body central-force problems


Distribution of orbital velocities in a disk galaxy for N-body simulation?


What is the relation between Noether's theorem and uncertainty relation?

Conjugate Variables, Noether's Theorem and QM


Is the law of the equality of inertial and gravitational mass valid in all possible cases?


Heisenberg Uncertainty Principle scientific proof


Query about approaches to extract energy out of Quantum Vacuum Fluctuations

Can energy be taken out of the QFT vacuum?


Glowing metal: different visual spectrum?

Why does thermal radiation only occur at infrared and visible frequencies?


Why do groups in the periodic table have missing periods?

Why do electrons not fully fill up all the orbitals sequentially?


Current divided into components like vectors


Electric lamp and City electricity frequency

What invisible flicker do different types of light bulbs have?


Smallest Aperture for $HCl$ to pass through

How to find out the maximum radius of a hole that can keep water stay in a container by water viscosity?


What exactly are the high energy problems between general relativity and quantum field theory?

Why is Einstein gravity not renormalizable at two loops or more?


Comparison of Gravitation pull on moon due to sun and earth

Why does the Moon not revolve around the Sun directly?


What does the line above a letter represent?

What does $\bar{y}$ with a line over it represent?


Confusion over the standard units used in special relativity and particle physics?

How can the speed of light be a dimensionless constant?


How does a photon lose intensity as it passes through space?

Why does a light wave fade as it travels through space?


Particles can be at the same time in two places. Why?

Can an electron be in two places at the same time?


Is there any electromagnetic radiation associated with the electrons moving in the conductor?

Does a conducting wire give off measurable radiation?


Why is light affected by gravity even though it is massless?


Why do high frequencies have a larger deflection through a prism than smaller frequencies?

Why do prisms work (why is refraction frequency dependent)?


Is there any existing mathematical work which connects the "entropy" with the "arrow of time"?

Is there a mathematical relationship between time and entropy?


Why do we use microwaves in microwave oven?


Physical interpretation of product of inertia

What is the physical significance of the off-diagonal moment of inertia matrix elements?


In Inelastic collision, momentum is conserved while Kinetic Energy is not, Why?

How can momentum but not energy be conserved in an inelastic collision?


Intensity of electric field and electric potential


Why some materials pass light and others do not?


What is outside the boundaries of our universe (Future horizon)

If the universe is expanding, what is it expanding into?


Why work done by gravity on a satellite moving around earth is zero?


Why do gravitational mass and inertial mass appear to be indistinguishable?

Is there a fundamental reason why gravitational mass is the same as inertial mass?


How is weight distributed in a stack of boxes?


Query on magnification by concave mirror


How much time would it take for a black hole size of a proton to suck up a pen?

How fast a (relatively) small black hole will consume the Earth?


Difference between $\Delta$, $d$ and $\delta$


Would two perfectly smooth surfaces of metal atoms bond together?

Why don't metals bond when touched together?


Are those equations in error propagation related?


Variation Weight of vessels filled with same fluid

Does the shape of a containter affect the apparent mass of liquid inside it when measured by a scale?


Does infinite mass mean infinite gravitational force?


Is there a quasistatic process that is not reversible?


Quantum entanglement used for FTL communication?

"FTL" Communication with Quantum Entanglement?


Age of universe and its relativistic effect

Effect of space time relativity on the age of the universe?


Acceleration of a particle at the speed of light

What happens when a photon hits a mirror?


Definition of time & its connection with movement of material. In physics we deal with material & without material time cannot be imagined

What is time, does it flow, and if so what defines its direction?


Newton's third law and movement of 2 objects in contact

How to explain the force applied on this object?


Planck length, planck time, and planck rotation?

Does the Planck scale imply that spacetime is discrete?


What is the process that leads to the volume expansion of the outer layers of a star when it becomes a red giant?

What causes the dimensions of a star increase when its hydrogen fuel is exhausted?


Could the equations of physics evolve over time?


If centripetal force and centrifugal force acting on an electron is equal, then what makes electron to revolve the nucleus?

Why don't electrons crash into the nuclei they "orbit"?


Why can't $ i\hbar\frac{\partial}{\partial t}$ be considered the Hamiltonian operator?


What exactly the Heisenberg Uncertainty Principle explains?

Can the Heisenberg Uncertainty Principle be explained intuitively?


How to describe what is conformal bootstrap and what's its application in renormalization group?

Looking for intro to Conformal Bootstrap


Is there any chance that the EM drive thrust could be caused by quantum tunnelling?

What are the proposed theoretical explanations for the EmDrive?


If energy can't order itself, how did energy get ordered or made?

How can it be that the beginning universe had a high temperature and a low entropy at the same time?


Do higgs field affect rest mass and relativistic mass?

How does the Higgs field enable masses to attract each other?


What does that sin wave of a photon represent?


What happen if an electron meets another electron?

What happens in electron-electron collisions?


Why do things look smaller when farther away?


Why is this non-linear transformation not a Lorentz transformations? It does preserve $x^2 + y^2 + z^2 - c^2t^2 = x'^2 + y'^2 + z'^2 - c^2t'^2 $

Interval preserving transformations are linear in special relativity


What would it look like if we broke the speed of sound underwater?


Left-handed and right-handed helicity, can you explained well the phenomenon of chirality simply?

What is polarisation, spin, helicity, chirality and parity?


How does a bicycle remain stable when in motion?

Why doesn't a bike/bicycle fall if going with a high speed?


Is there a way to calculate the time taken by a falling object to reach terminal velocity?

Calculating time to reach certain velocity with drag force


Gear Theory -- Entanglement -- Spooky action at a distance explained?

Is it possible for information to be transmitted faster than light by using a rigid pole?


Resource recommendation for undergraduate-level wave mechanics?

What's a good textbook to learn about waves and oscillations?


Calculating the distance between two masses with respect to gravitational force

Integrating radial free fall in Newtonian gravity


Trouble understanding internal and external forces

Do internal forces cause change in velocity?


How can an electrically neutral planetary core be geodynamo?


Normalization of basis vectors with a continuous index?


How did the constant $\pi$ creep into Einstein's field equation?


Is the wave-particle duality a real duality?


Are there such things as internal-external forces?


Why don't I accelerate upwards due to reaction force?


Difference between live and neutral wires


In the double-slit experiment of electrons (observed by photons), is it correct to say the collapse is caused by the momentum of the photons?


If the Pauli Exclusion Principle is not a force, how does it result in pressure, or change the momentum of particles?

Is the electromagnetic force responsible for contact forces?


Where should a physicist go to learn chemistry?


How do electrons actually move in a wire?

How does electricity propagate in a conductor?


Stretch length of horizontal and vertical springs


Do charges affect each other instantaneously?

Do electrostatic fields really obey "action at a distance"?


Are the planets revolving around the sun in perpetual motion?

Are orbiting planets an  example of perpetual motion?


How does the infinite density of the early universe or black holes not violate Fermi-Dirac statistics?

Does black hole formation contradict the Pauli exclusion principle?


Why don't electrons in atoms radiate away their energy?

Why don't electrons crash into the nuclei they "orbit"?


How to mathematically work out the color of the sky?

How to correctly calculate the colour of the sky?


Why is $k$ taken as 1 in the derivation of $F=kma$?

How do we know that $F = ma$, not $F = k \cdot ma$


How does a reflected photon keep its entanglement

Why doesn't a typical beam splitter cause a photon to decohere?


Static Friction and Centripetal Force for woman attached to spinning disc


Electron drift velocity does not explain observed results

What is the reason for extremely high speed of electric current?


Is the surface of the Earth expanding in GR?


Usage of singular or plural SI base units when written in both symbol as well as name


At a microscopic level, how does friction come into exist?

How is frictional force dependent on normal reaction?


Could a strong enough electric field tear a hydrogen atom apart?

Can electromagnetic fields be used to deconstruct and reconstruct atoms?


Why is small work done always taken as $dW=F \cdot dx$ and not $dW=x \cdot dF$?


Why do we feel cold when we switch on the fan?


$\Delta U = n C_v \Delta T $ non-constant volume


Why does the temperature of the early Universe decrease as it expands?

Why the temperature is getting lower when the universe is expanding


Magnetic force created from a point charge due to an inertial frame

Magnetic force on a charged particle viewed from 2 inertial frames


Can black holes form in a finite amount of time?


Has the speed of light changed over time?


How does a photon experience space and time?


Electron falling into an extreme black hole and Cosmic Censorship Hypothesis

What prevents the accumulation of charge in a black hole?


Big bang singularity in an infinite universe


How does spacecraft/rockets accelerate in vacuum while there's no gas present to apply force on in order to accelerate?

What is a rocket engine thrusting against in space?


Why is the value of $g$ 0 in Earth's center?

Would you be weightless at the center of the Earth?


Contractions between big bang and gravitational law


Lorentz transformations: new actual notation for a $4$-vector


Clarification on factors of $c$ in the Lorentz' force


What are the prerequisites to studying general relativity?


What is known about the topological structure of spacetime?


Shooting a single photon at a 1/2 transparent 1/2 mirror 45 degree piece of glass

What happens when a photon hits a beamsplitter?


why do magnetic field lines leave the north pole and enter the south pole?


What is particle spin in terms of waves?

What is spin as it relates to subatomic particles?


Electrical flow in a simple parallel circuit


Isn't the uncertainty principle just non-fundamental limitations in our current technology that could be removed in a more advanced civilization?


In Quantum Physics would a camera count an observer that causes wave collapse?

What is an observer in quantum mechanics?


What is the math knowledge necessary for starting Quantum Mechanics?


Argument for the Smallest Division of Time?

Does the Planck scale imply that spacetime is discrete?


Physical meaning of Maxwell's equations and origin of EM waves


How does alternating current provide energy?


How does angular momentum get quantized?


What equations so I can model a "bouncing particle"?


Lightning in space, would it be a perfectly straight line?


Why does a ray passing through optical centre remain undeviated?


Proving that test particles in GR, follow spacetime geodesics

Why do objects follow geodesics in spacetime?


I don't get the concept of "God plays with dice" - In what scenario is it proven that he does?

Is the universe fundamentally deterministic?


What are the various physical mechanisms for energy transfer to the photon during blackbody emission?


What's so special about the speed of light?

What is so special about speed of light in vacuum?


mathematical relationship between height of drop and horizontal splash distance


Tension in string due to two opposite forces

Why I think tension should be twice the force in a tug of war


How is viscosity described on the molecular level?


Dimensions in the logarithmic form of the Arrhenius equation

What is the logarithm of a kilometer? Is it a dimensionless number?


Is the gravitational waves velocity also $c$, regardless the adopted inertial frame, and the source movement conditions?


Is $E^2=(mc^2)^2+(pc)^2$ correct, or is $E=mc^2$ the correct one?


What is the rate at which the field of an electron spreads?


What's the physical meaning of the imaginary component of impedance?


Why do we detect neutrinos from core collapse SNR 2 hours before we detect light?

Neutrinos arrived before the photons (supernova)


Can there be true instantaneous/stepped acceleration?

When motion begins, do objects go through an infinite number of position derivatives?


Why do harmonics occur when you pluck a string?


Young's double slit experiment for a single photon

Single Photon Single Slit Interferometry


How can you separate sub atomic particles and manipulate them?

How are the protons for collisions in the LHC made?


In an alternating current, do electrons flow from the source to the device?


Why are angles dimensionless and quantities such as length not?


what is the value of the acceleration of a bar magnet falling through a coil?

The fate of a bar magnet released in an infinitely long copper tube


What is the difference between weight and mass?


Tangential Velocity in Large Rotating Objects

Rotate a long bar in space and get close to (or even beyond) the speed of light $c$


Does relative velocity also depend on the distance from which moving object is being viewed?

Why do far away objects appear to move slowly in comparison to nearby objects?


If energy delivered to the resistor is not the kinetic energy of the electrons then how is it delivered?


Significance of $c$ squared in Einstein energy mass formula

What is the meaning of speed of light $c$ in $E=mc^2$?


Can forces from outside the observable universe be observed through a distant object?

Is it possible to learn about an event that occurred outside of your observable universe?


Why is Hamilton's Principle not the 'Principle of Least Action'?

Action and Action integral: Different kinds of variational principles


Difference between measurement, state and system in quantum mechanics

Differences in measurement between quantum physics and classical physics?


Interpretation of Weinberg-Witten theorem

Gauge symmetries and elementary particles


What really causes light/photons to appear slower in media?


Why are metals generally cooler compared to their surrounding?

Why does cold metal seem colder than cold air?


If you fall for a long enough period of time, would you eventually hit or break the speed of light?


Do neutrinos change speed in neutrino oscillations?

Neutrino Oscillations and Conservation of Momentum


The difference in form of the term and counter-term in the renormalized Lagrangian

Why do the counterterms in renormalized $\phi^4$-theory with power two in fields give vertices and not propagators?


How to know the distance of the black hole merger?

How were the solar masses and distance of the GW150914 merger event calculated from the signal?


Why is there a $\frac{1}{2}$ in the kinematic equation?

Why there is a $\frac{1}{2}$ in the distance formula $d=\frac{1}{2}at^2$?


Gaining intuition over central extension of algebras

Why exactly do sometimes universal covers, and sometimes central extensions feature in the application of a symmetry group to quantum physics?


Why do all the planets of the solar system orbit in roughly the same 2D plane?


Can the Schrodinger equation describe planetary motion?

Can a quasiclassical electron wave packet in elliptic orbit be formed from bound hydrogen-like eigenstates?


Michelson-Morley Experiment Why 90-degree rotation

Why shift in fringe is expected in Michelson Morley Experiment?


Can matter actually go "inside" a black hole?

How can anything ever fall into a black hole as seen from an outside observer?


Is spin really just "rest angular momentum"?

What is spin as it relates to subatomic particles?


Conservation of momentum: Acrobat and monkey

Can linear momentum be conserved before and after collision in the presence of an external force?


Radioactive Dating Accuracy After 60,000 years

Why is carbon dating limit only 40,000 years?


Suggestion for books about mathematics of quantum entanglement and computation


During big bang, everything expands same rate, homogenous, isotropic, nothing pulled towards each other. Did quantum randomness form stars, galaxies?

Was the singularity at Big Bang perfectly uniform and if so, why did the universe lose its uniformity?


Behavior of a gravitation field of an object falling into a black hole

Can you have a giraffe shaped black hole?


Force times Displacement conserves itself

How was the definition and the formula of work derived? Is it the best possible?


What is a good book for learning mechanics at the JEE advanced level?


What is time, does it flow, and if so what defines its direction?


Does the conservation of the Wronskian follow from Noether's principle?