A collision in which there is absolutely no loss of `K.E.` is called an elastic collision. In such a collision, the linear momentum , total energy and kinetic energy, all are conserved.The coefficient of restitution `//` resilience of perfectly elastic collisions is unity.
Read the above passage and answer the following questions `:`
(i) When two bodies of equal masses undergo perfectly elastic collision in one dimension, what happens to their velocities ?
(ii) How is this fact applied in a nuclear reactor ?