A billiard cue ball with a mass of 0.60 kg and an eight ball with a mass of 0.55 kg are rolled toward each other. The cue ball has a velocity of 3.0 m/s at 0 ("to the right"), and the eight ball has a velocity of 2.0 m/s at 90. After the collision, the cue ball moves off at a velocity of 2.0 m/s at 40. a. What is the velocity of the eight ball? (5 marks) b. Prove whether or not the collision is elastic. (2 marks)