Question

To verify the law of conservation of mass which kind of set up is appropriate

Answer 1

the set in which there is no any sort of resistive affect because if there won't be any resistive affect like friction so the force applied be converted into work

Answer 2

the place where the law of conservation of mass is to be verified is an isolated place because if there is no isolated place then the mass can be formed into energy and go out from there and the result it may be affected