What are the correct heights for Tom after a collision with Dan in a halfpipe?

[mcrwinner]

Homework Statement

Dan and Tom are skateboarding in a large semicircular halfpipe. Dan starts out from rest at a height h and collides with Tom standing at the bottom. Dan and Tom have about the same mass. After the collision, which height will Tom reach? Let's neglect friction and consider the following two extreme cases:
a) The collision is totally inelastic.
b) The collision is elastic. [/B]

Homework Equations

H = v² / 2g

The Attempt at a Solution

For part a) = V²/4 / 2g leaves them at h/4
For part b) = v^2/4/2g leaves them at h/4

Part a is correct but part b isn't. Any help would be appreciated[/B]

 

[gneill]

You need to show how you arrived at your answers. How can we help if we can't see where you went wrong?