A wedge having mass M is placed on a horizontal floor and a wooden cube of mass m (m is less than M) is placed on the top of this wedge. Friction is absent everywhere. If we let the smaller wooden cube to move down the wedge then what will be the velocity of the wedge when the wooden cube reaches the bottom of the wedge..

Question

anonymous · Answer

Depends what you have picked as a center of your coordinate system. If its at some point near the wedge at floor level, then the wedge would not be moving and will have zero velocity.

vincent-lyon.fr · Answer

The system {wedge + cube} has no horizontal acceleration. So its centre of mass goes down but does not move horizontally.

You can also use conservation of mechanical energy.