Finding average force when momentum change is zero in elastic collision

[zeromodz]

Okay we all know that the average force equation is

ΔP = FΔT
F = ΔP / ΔT


Say I throw a ball at the wall and it has and the collision is elastic. Therefore, the initial momentum equals the final momentum and therefore.

ΔP = 0

I still know that there is a force exerted on the wall, but how do I find it if ΔP = 0?

 

[SimonRoberts]

Don't forget that momentum is a vector quantity. So if it hits the wall with momentum magnitude P, the change in momentum is 2*P , to account for the reverse in direction.

Hope this helps,

Simon