# Solve the following :

Question:

Consider a gravity-free hall in which a tray of mass $M$, carrying a cubical block of ice mass $m$ and edge $L$, is at rest in the middle. If the ice melts, by what distance does the center of mass of "the tray plus the ice" system descend?

Solution:

As ice melts, COM would no shift, as there is no external force (not even gravity).