Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsMass on a Spring: Simple Harmonic Oscillatorhttp://demonstrations.wolfram.com/MassOnASpringSimpleHarmonicOscillator/]]>http://demonstrations.wolfram.com/MassOnASpringSimpleHarmonicOscillator/Atwood's Machine with Rotational Inertiahttp://demonstrations.wolfram.com/AtwoodsMachineWithRotationalInertia/]]>http://demonstrations.wolfram.com/AtwoodsMachineWithRotationalInertia/