1. Car A hits car B (initially at rest and of equal mass) from behind while going 35 m/s….

1. Car A hits car B (initially at rest and
of equal mass) from behind while going 35 m/s. Immediately after the collision,
car B moves forward at 25 m/s and car A is at rest. What fraction of the
initial kinetic energy is lost in the collision?

2. Prove that in the elastic collision of
two objects of identical mass, with one being a target initially at rest, the
angle between their final velocity vectors is always 90°.