Dr. Andy Ruina at Cornell demonstrating a simple mass-spring setup on an air track.
Sliding along a Curved Track from the Wolfram Demonstrations Project by Erik Mahieu
A ball freely moving on a 1-D custom bowl, with normal forces.
Courtesy of the Wolfram Demonstrations Project
(Trouble? Download and install the Wolfram CDF player here. We use it a lot, and it does some really cool stuff.