# A ball of mass 0.220 kg that is moving with a speed of 7.5 m/s collides head on and elastically with

A ball of mass 0.220 kg that is moving with

a speed of 7.5 m/s collides head on and elastically with another ball initially

at rest. Immediately after the collision, the incoming ball bounces backward

with a speed of 3.8 m/s. Calculate (a) the velocity of the target ball after

the collision, and (b) the mass of the target ball.