1. A 0.150-kg baseball moving at a speed of 45.0 m/s crosses the plate and strikes the 0.250-kg catcher's mitt (originally at rest). The catcher's mitt immediately recoils backwards (at the same speed as the ball) before the catcher applies an external force to stop its momentum. a. Determine the post-collision velocity of the mitt and ball.

b. Solve for the total kinetic energy before and after collision.