Question

A large wedge rests on a horizontal frictionless surface, as shown. A block starts from rest and slides down the inclined surface of the wedge, which is rough. During the motion of the block, the center of mass of the block and wedge system:

• A. does not move
• B. moves vertically with increasing speed
• C. moves horizontally with constant speed
• D. moves both horizontally and vertically

Answer 1

The correct option is B moves vertically with increasing speed

Since there is no net external force acting on the system in horizontal direction, thus the center of mass remains at rest in horizontal direction. A net external gravity force acts on the system in downward direction, so center of mass accelerates downward. Thus option B is correct.