physic
posted by dan .
1. A 57 g tennis ball is moving to the left at 36.2 m/s. It collides with a wall and rebounds to the right. The tennis ball is in contact with the wall for 0.107 s and it loses 14% of its kinetic energy during the impact. What is the average force (magnitude & direction) exerted by the wall on the tennis ball?

you know KE initial, you know final KE is .86 of that. Solve for Vfinal from that.
Force= mass (Vi+vf)/time
notice the vf is added (it is a minus for the change in direction, so minus a minus is + 
i still dont understand how to find the v final.
Can you show an example @bobpursley 
i still dont understand how to find the v final.
Can you show an example @bobpursley