# physics

posted by .

A baseball (m = 151 g) approaches a bat horizontally at a speed of 39.8 m/s (89 mi/h) and is hit straight back at a speed of 45.7 m/s (102 mi/h). If the ball is in contact with the bat for a time of 1.05 ms, what is the average force exerted on the ball by the bat? Neglect 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.

• physics -

Force * contact time = impulse
= momentum change
= 0.151 kg*(45.7 + 39.8)m/s

Solve for the force in Newtons. You do not have to consider the weight of the ball, since it is in a different (vertical) direction from the force of the bat, anyway. The choice of positive direction also doesn't matter. Whoever wrote this question is just making it harder with the "hints".

• physics -

When I did this I got the answer 12.91 prior to you responding to me and when I tried the way you said I received the same answer but our software is telling me that its wrong and i tried twice.