What Happens to Energy When a Ball Bounces off a Wall?

[yamugushi]

Change in momentum of a ball

Please note, instead of making a new thread I just edited my new question into this thread

Homework Statement

A ball is rolled into a wall and bounces back at the same speed, the change in momentum is?

Homework Equations

Ein = Eout

The Attempt at a Solution

I thought it was m(v) but I got it wrong (doing test corrections ATM)

 

[JaWiB]

Conservation of energy.

Where does that 100J go when the bow is pulled back and held in place? After the archer releases, where is the energy at the instant when the arrow leaves the bow, and how does that help you estimate its velocity at that instant?

 

[yamugushi]

Conservation of energy.

Where does that 100J go when the bow is pulled back and held in place? After the archer releases, where is the energy at the instant when the arrow leaves the bow, and how does that help you estimate its velocity at that instant?

Oh, I get it, set E_p
to E_k
I was looking at W - P equations