Calculating Average Force: Momentum Question

[Andy87055]

This seems like an easy question.
A 0.145 kg baseball pitched at 39.0 m/s is hit on a horizontal line drive straight back toward the pitcher at 52.0 m/s. If the contact time between the bat and ball is 0.001 seconds, calculate the average force between the ball and bat during contact.

I used Average Force= change in momentum divided by change in time.
I figured the change in momentum to be 1.89 kg*m/s and change in time to be .001 seconds. Dividing, I got 1,890 N. The answer given by the textbook is 13,200 N.

 

[Tide]

HINT: The change in velocity is 91 m/s.

 

[andrewchang]

you need to use the change in velocity. make sure to take the directions into account.

edit:

tide beat me to it! =p

 

[Tide]

Gotta be quick, Andrew! ;)

 

[Andy87055]

That's right, i forgot velocity was changing directions. Thank you.