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.