Physics- a simulation.
This is what I did for my AP Physics class. Basically, you can edit the velocity and the position as well as the radius and color of up to 10 spheres. They bounce around the screen colliding with each other. The total kinetic energy and momentum are displayed. You can take screenshots using the screenshot button (this also generates a file with raw data). Well, have fun and experiment with it. Tell me if you think it works properly.
This project has its own website with algorithms, code, and everything else: http://2dcollisions.tripod.com
Download it here. (283 Kb)