Question

A body moving towards a finite body at rest collides with it. It is possible that 

(a) both the bodies come to rest 

(b) both the bodies move after collision 

(c) the moving body comes to rest and the stationary body starts moving 

(d) the stationary body remains stationary, the moving body changes its velocity.

Answer 1

(b) both the bodies move after collision
(c) the moving body comes to rest and the stationary body starts moving

Explanation: 

Since one of the bodies has some velocity before collision hence total momentum of the bodies is nonzero. Since in the absence of external force total momentum is conserved, both the bodies cannot come to rest. Because then the total momentum will become zero. (a) is not true. 

In both the options (b) and (c) it is possible that final momentum is equal to the initial momentum. 

The option (d) is not possible because the total momentum will not remain the same as before the collision.