- #1
MuIotaTau
- 82
- 3
How do we know that the work-energy theorem holds for variable mass systems? Or rather, since I'm sure that we can at least know it to be true experimentally, what is the mathematical basis for the work-energy theorem? I know for fixed mass systems, a rather simple derivation comes from integration Newton's second law over an infinitesimal displacement, but I've never seen any sort of derivation of the relationship for variable mass systems, only the assumption that it holds. So purely out of curiosity, does any such demonstration exist?