1:44 AM
1

Why is mass a very concentrated form of energy? Does it have to do something with photons, phonons or nucleus?

2 hours later…
3:43 AM
4

Say I have a charge density $\rho(\vec{x})$ in some finite volume $V$, such that all of the multipole expansions apart from the monopole moment (meaning dipole, quadrupole and so forth) are zero. Does this mean that $\rho(\vec{x})$ is spherically symmetric? I know the opposite is true - meaning, ...

16 hours later…
8:02 PM
3

Consider this situation: The ball is moving forward and undergoing rotation. Assume that it is not slipping. Now eventually the rotation of the ball slows down and the ball eventually comes to a halt. But if you observe the direction of friction (when body is rotating clockwise), you will se...