Tennis Racket Dynamics: Impacts, Forces & Weight

[aligass2004]

Homework Statement

A tennis player swings her 1000g racket with a speed of 8m/s. She hits a 60g tennis ball that was approaching her at a speed of 18m/s. The ball rebounds at 38 m/s.
a.) How fast is her racket moving immediately after the impact? You can ignore the interaction of the racket with her hand for the brief duration of the collision.
b.) If the tennis ball and racket are in contact for 10ms, what is the average force that the racket exerts on the ball?
c.) How does this compare to the ball's weight?

Homework Equations

The Attempt at a Solution

I tried using m1v1 = m2v2 for part a, but I don't think it's right to use that equation in the first place.

 

[Hootenanny]

I tried using m1v1 = m2v2 for part a, but I don't think it's right to use that equation in the first place.

Why don't you think that its the correct equation to use?