A block of mass `m` rests on a stationary wedge of mass M. The wedge can slide freely on a smooth horizontal surface as shown in figure. If the block starts from rest

Options

A. (a) the position of the centre of mass of the system will change
B. (b) the position of centre of mass of the system will change along the vertical but not along the horizontal
C. (c) the total energy of the system will remain constant
D. (d) All of the above

Answer

D

Explanation

Net horizontal force on system is zero. Therefore, centre of mass does not move in horizontal. Further, all surfaces are smooth. Therefore mechanical energy of the system remains constant.