# Physics, please help

posted by
**amber**
.

Hello,

I don't know how about to answering this question:

work out the problem of a ball of mass m that falls a distance h from rest. It hits the floor and rebounds to its starting height. (a) What total time ie required for the motion? (Neglect the time of contact with the floor.) (b) What is the speed of the ball as it strikes the floor? (c) What is the change in momentum of the ball as it strikes the floor and rebounces? (d) Calculate the average force that the ball exerts on the floor averaged over the whole time interval of part (a). Is this surprising?

Is there like a formula in particular that I should be looking at?

The return bounce takes as long as it takes to fall, so find the time of fall and double it.

h=1/2 g t^2 solve for time.

speed= g * time

change of momentum= 2* momentumat floor

= 2*m*speed

The force of the ball is gravitational pull, which is mg. That is the force on the ball, and it is the force on the Earth.

You can get the force also by doing change of momentum/totaltimefalling.

Neat. This doesn't surprise me, gravity is gravity.