Question

A ball hits the floor and rebounds after an inelastic collision. In this case-

• A. The momentum of the ball just after the collision is the same as that just before the collision
• B. The mechanical energy of the ball remains the same in the collision
• C. The total momentum of the ball and the earth is conserved.
• D. None of these

Answer 1

The correct option is C The total momentum of the ball and the earth is conserved.

(A) As we know, momentum is a vector quantity, so as the ball rebounds, the direction of velocity has been changed, the direction of momentum also changes, and hence it can not be the same as before.
(B)$\because$ Collision is inelastic; therefore, the mechanical energy is not to be conserved.
(C) Momentum of earth + ball system is conserved since there is no external force.