Two identical ball bearings in contact with each other and resting on a frictionless table are hit head-on by another ball bearing of the same mass moving initially with a speed v. If the collision is elastic, which of the following (figure) is a possible result after collision?
We know that when two bodies of same mass collide, they interchange their velocities. When first ball collides with the combinations of balls 2 and 3, the first ball comes to rest while ball number 2 moves with velocity v again it collides with ball number 3 and hence ball number 2 comes to rest while ball number 3 moves with velocity v.
Hence, the situation shown in Fig. (ii) is the correct result of collision.