8. (a) (i) State the law of conservation of linear momentum.
(ii) Define the term “elastic collision”.
(b)A body of mass 8 kg moving with a velocity of 20 m/s collides with another body of mass 4 kg moving with a velocity of 10 m/s in the same direction. The velocity of the 8 kg body is reduced to 15 m/s after the collision. If the bodies do not stick together after the collision, calculate the final velocity of the 4 kg body.