A block of mass `m` slides down a wedge of mass `M` as shown . The whole system is at rest , when the height of the block is `h` above the ground. The wedge surface is smooth and gradually flattens. There is no friction between wedge and ground.

As the block slides down, which of the following quantities associated with the system remains conserved ?

Options

A. Total linear momentum of the system of wedge and block
B. Total mechanical energy of the complete system
C. Total kinetic energy of the system
D. Both linear momentum as well as mechanical energy of the system.

Answer

B

Explanation

Linear momentum is conserved only in horizontal direction.