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## Homework Statement

A football player whose mass is 85 kg throws a football with a mass of 0.8 kg against a post. The football hits the post traveling horizontally with a speed of 25 m/s, and then it bounces back with about the same speed. The football is in contact with the post for 0.05 s. What average force is exerted on the post by the ball?

m = 0.8 kg

vi = 25 m/s

vf = -25 m/s

t= 0.05s

## Homework Equations

FΔt=m(vf-vi)

F = [itex]\frac{m(vf-vi)}{Δt}[/itex]

## The Attempt at a Solution

F = [itex]\frac{0.8(-25-25)}{.05-0}[/itex] = -800N by the post.

Is the mass of the football player irrelevant?