Coefficient of Restitution

[SuperGeek]

Hi all,
I am trying to find the coefficient of restitution in this example:
Block m1=2 kg is pushed with initial velocity v=7 m/s for distance
d = 4 meters towards a wall. Kinetic friction b/w floor and block is mK = 0.4. The block rebounds off the wall and travels distance
d2 = 1 m before stopping.

I think I should get the speeds of the block right before and after hitting the wall first but I am really lost on this one. Any help or teaching would be appreciated.

[Doc Al]

Originally posted by SuperGeek
I think I should get the speeds of the block right before and after hitting the wall first but I am really lost on this one. Any help or teaching would be appreciated.
Yes, you need to find the speed of the block before and after the collision. First find the acceleration of the block, using Newton's second law. Then use the formula for accelerated motion to find the speeds:

Vf2 = Vi2 + 2aΔX

(This should really be in the homework help section!)