I have tried to work this one out and really can't get it.

We have two carts that have magnets to keep them from touching. One cart is initially at rest and we push the second cart towards it. Because the two carts will not actually touch, the collision is elastic. Use the data given to find all the unknowns. Note that v1' is the velocity of cart 1 after the collision.
Mass 1: .51 kg
Mass 2: .50 kg
V1: 1.2 m/s
Unknowns are
V1'= ?
V2'= ?
P1= ?
P1'=?
% difference =?
KE1'= ?
KE2' = ?
% difference = ?

2 answers

I hope you realize that v2 is zero.

You have two equations, two unknowns:
M1V1+M2V2=M1V1' + M2V2' solve that for V2' in terms of all the other.

1/2M1 V1^2+1/2 M2 V2^2=1/2 M1V1'^2 + 1/2 M2V2'^2
put the numbers you have for V2' into that, and start solving for V1'. Note: a bit of algebra is involved.

after you know V1',V2' the rest is easy.
Yea I do know about V2. And thanks so much, I really appreciate it!