Posted by Sarah on .
A .145kg baseball pitched at 39m/s is hit on a horizontal line drive straight back toward the pitched at 52m/s. If the average force the bat exerts on the ball is 13,200N, how long did the collision last?

Physics 
Damon,
You are asking the same basic question over and over slightly different ways.
average force = change in momentum / change in time
Just do it.