Calculating Fmax in a Tennis Ball Collision

[macgirl06]

I am having trouble with this question, I know what I need to find, just don't know what route to take.

A 53.0 g tennis ball with an initial speed of 30.5 m/s hits a wall and rebounds with the same speed. The figure below shows the force of the wall on the ball during the collision. What is the value of Fmax, the maximum value of the contact force during the collision, if the force is applied for ti=26.4 ms?

I was wondering should I use Fnet=ma to find Fmax, but find acceleartion first

Any help would be great
Thanks

 

[radou]

The figure doesn't work. You may want to post a link or something.

 

[macgirl06]

I have attached the diagram, its a word document