Calculating the Net Force of a Bouncing Ball

[_wolfgang_]

Homework Statement

a rubber ball mass of 0.08 kg bounces vertically on a concrete floor. the ball strikes the floor at 10 ms-1 and rebounds at 8 ms-1. The time in contact with the floor is 0.05 sec.
Calculate the average net force acting on the ball during the contact with the floor.

Homework Equations

E=F/t

F=0.5mv^2

The Attempt at a Solution

(0.5x0.08x10^2)/0.05
= 80N

I get a force of 80 N but to me it seems to much to be true... Help?

 

[rl.bhat]

You have to find the average force which is found by
F= (change in momentum)/time.

 

[_wolfgang_]

You have to find the average force which is found by
F= (change in momentum)/time.

So change in momentum= 1.44 kgms-1

F=1.44/0.05
=28.8N

that seems more plausible Thanks for the help!