Enhanced EOC Problem 927 A tennis player swings her 1000 g r

Enhanced EOC: Problem 9.27

A tennis player swings her 1000 g racket with a speed of 14.0 m/s . She hits a 60 g tennis ball that was approaching her at a speed of 20.0 m/s . The ball rebounds at 38.0 m/s .

For help with math skills, you may want to review:

Solving Algebraic Equations

Part 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.

Express your answer with the appropriate units.

Part B

If the tennis ball and racket are in contact for 13.0 ms , what is the average force that the racket exerts on the ball?

Express your answer with the appropriate units.

Solution

A)

Momentum before = 1 . 14 – 0.06 . 20 = 12.8 kgm/s
Momentum after = 12.8 = 1 . V + 0.06 . 38

V_racket = 10.52 = 10.52 m/s

B)

F . t = mv

F _(average) = 0.06 ( 38 + 20 ) / 0.0130 s = 267.69 N