1. The problem statement, all variables and given/known data Consider a gravity free hall in which a tray of mass M,carrying a cubical ice block of mass m and edge L,is at rest in the middle.If the ice melts,what would be the displacement of the system? 2. Relevant equations 3. The attempt at a solution I think it has to do with the conservation of momentum,since no external force is acting.But i cannot think further.Please help.