Having real trouble with the question below that is part of my engineering course. I've sussed question 6 but making no headway with Q7.
A ball of mass 0.2 kg collides elastically with a heavier ball (mass 0.5 kg) which was originally stationary. The initial speed of the lighter ball is 12 m s1. The collision was head-on, with both balls moving away along the same line as the incident ball. What is the speed of the heavier ball after the collision?
In the question above, suppose that the collision was not head-on and that the lighter ball was deflected through 90º. Assuming still that the collision is elastic, what is the final speed of the lighter ball?