Calculating Average Force in a Ball Rebound Momentum Problem

[lmc489]

A .3 kg ball is dropped from a height of 2 m. It strikes the group and rebounds to a height of 1.5 m. The collision with the ground lasts for .01 seconds. The average force exerted by the ground on the ball is:

a)280
b) 540
c) 430
d) 350

So, i know that we have to use some type of formula involving mgh which equals velocity?

I did:

.3 [ rad 2mgh +rad 2 mgh] / .01 = 350

is this correct?

 

[einstein_a_go_go]

yes - from whence came your equation?