This simulation explores mechanical energy conservation with and without friction. There are three scenarios to choose from. The first is frictionless, the second includes friction, and the third lets you build your own track.

[list=1][*]If you place the skater on the edge of the U-shaped track, she will stay on the track, but if you drop her onto the track, she sometimes flies off the far end. Why?[/*][*]Where does the skater's thermal energy come from?[/*][*]In the "Playground" scenario, you can setup a loop-the-loop. How high above the loop does the skater need to start to be able to make it?[/*][*]Notice that you can change whether the skater "sticks" to the track when upside down. What effect does this have on being able to complete a loop-the-loop?[/*][/list][br]Credits:[br]PhET Interactive Simulations[br]University of Colorado Boulder[br]https://phet.colorado.edu