Question

A small block of mass m and a concave mirror of radius R fitted with a stand lie on a smooth horizontal table with a separation d between them. The mirror together with its stand has a mass m. The block is pushed at t = 0 towards the mirror so that it starts moving towards the mirror at a constant speed V and collides with it. The collision is perfectly elastic. Find the velocity of the image (a) at a time t < d/V, (b) at a time t > d/V.

Answer 1

b) After a time t > d/V, there will be a collision between the mirror and the mass.
As the collision is perfectly elastic, the object (mass) will come to rest and the mirror starts to move away with same velocity V.
At any time t > d/V, the distance of the mirror from the mass will be