In thermodynamics, it is frequently said that work and heat are path functions with inexact differentials $\delta Q$, $\delta W$, so one can not talk about a change in work or a change in heat since they are not state properties of the system. If so, why do I usually find power defined as the der...

Why can't we see light from beyond the observable universe? I've done a lot of research on this and all I've found is unsatisfactory answers and straight up nonsense. Some claim that the universe "expands faster than the speed of light" beyond the observable universe. Such a claim doesn't even ma...

Since the time it takes for the earth to complete one rotation about itself (i.e., the time we call "day") is not constant, then the angular speed is also not constant, that is, there is a non-zero angular acceleration. What is the corresponding torque(s) causing this angular accelaration?