Question

A block of mass m is placed at rest on a smooth wedge of mass M placed at rest on a smooth horizontal surface. As the system is released ,

• A. The COM of the system remains stationary
• B. The COM of the system has an acceleration g vertically downward
• C. Momentum of the system is conserved along the horizontal direction
• D. Acceleration of COM is vertically downward (a < g)

Answer 1

Answer: (C), (D)

The correct options are
C Momentum of the system is conserved along the horizontal direction
D Acceleration of COM is vertically downward (a < g)

Considering the wedge +block as the system, there is no external force acting on the system in the horizontal direction.
Hence, momentum will be conserved in the horizontal direction.
The acceleration of CM will be less than g and vertically downward since there is a net force acting on the system.