2d comment Is the lay explanation of the equivalence principle wrong? Also, I remember reading that a clock on an accelerating spaceship will run at different speeds when placed at different heights, which is consistent with the equivalence principle. Mar26 reviewed Approve Special relativity revisited Mar23 comment Do some of the laws of Thermodynamics break down in Quantum Mechanics? This is just me, but I interpreted the question as being about whether thermodynamics is applicable at the microscopic level, not whether there are quantum effects in macroscopic thermodynamics. But maybe OP will correct me. Mar21 comment How is the conservation of momentum satisfied in long-range attraction such as electromagnetism and gravity? How I wish virtual particles stopped being a thing. Mar20 comment Top speed for a human Proton $\ne$ photon. Mar16 reviewed Approve Applying rotation operator to spin Mar15 reviewed Approve Do we need Dark Energy to explain the acceleration of the expansion of the universe? Mar13 reviewed Approve Stability of an unstable system using nonlinear element, is it possible or not? Mar11 comment Why isn't the path integral rigorous? Short answer: To define an integral rigorously, it's not enough to just say "and now take the limit $N \to \infty$". You need to prove that your discrete sum converges to something, and that it doesn't matter how you take the limit. Mar11 comment What is meant by the following divergent formula? This is one of those cases where physicists happily interchange limits when it in fact can't be done. However, without understanding the context (and I don't understand it), I can't say what the justification is. Mar1 reviewed Approve Confused about Gauss's Law for parallel plates Mar1 comment How does one normalize this wavefunction? The integral is actually pretty straightforward in cartesian coordinates. Feb28 comment Interstellar Movie: Black hole shown in the movie If it was actually light orbiting the black hole, then you wouldn't see it, because the light would be orbiting instead of actually reaching your eyes. Feb28 awarded Popular Question Feb27 comment What is the meaning of Einstein's field equation in terms of source and its effects on curvature? @VikramadityaMondal: Yes, that's exactly it. Everything that we're considering here is a function of $x^\mu$, and Einstein's equations are partial differential equations beteen tensors that are functions of space and time. Feb27 comment When generalizing from discrete (but infinite) eigenstates to continuous eigenstates, Why do we change the definition? I'm not sure that you can prove that $(2)$ is a generalization of $(1)$. All you can do is check that it has the same properties, or that one reduces to the other in some limit. Feb27 revised When generalizing from discrete (but infinite) eigenstates to continuous eigenstates, Why do we change the definition? Changed angle brackets Feb27 answered What is the meaning of Einstein's field equation in terms of source and its effects on curvature? Feb25 comment Is using molar terms with maxwells relations misguided? Number of moles is related to number of particles via Avogadro's constant. I'm sorry, but I'm not seeing what the big deal is here. Just replace $n$ with $N/N_A$. Feb24 reviewed Approve Electric potential vs potential difference