A baseball (m = 139 gram) approaches a bat horizontally at a speed of 38.5 m/s (86 miles per hour) and is hit straight back at a speed of 45.4 m/s (102 mi/h). If the ball is in contact with the bat for a time of 1.20 milliseconds, find the average force exerted on the ball by bat? Ignore the weight of the ball, since it is so much less than the force of the bat. Choose the direction of the incoming ball as the positive direction.