Question

A smooth sphere A of mass m collides elastically with an identical sphere B at rest. The velocity of A before
collision is 8 m/s in a direction making 60' with the line joining the centres at the time of impact. Which of
the following is/are possible.
(1) The sphere A comes to rest after collision
(2) The sphere B will come with a speed of 8 m/s afher collision.
(3) The directions of motion of A and B after collision are at right angles.
(4) The speed of B after collision is 4 m/s.​

Answer 1

Answer:

4 is the answer.

My confidence is saying that it is the answer