Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsSpring-Mass-Damper (SMD) System with Proportional Derivative (PD) Controllerhttp://demonstrations.wolfram.com/SpringMassDamperSMDSystemWithProportionalDerivativePDControl/]]>http://demonstrations.wolfram.com/SpringMassDamperSMDSystemWithProportionalDerivativePDControl/Free Vibrations of a Spring-Mass-Damper Systemhttp://demonstrations.wolfram.com/FreeVibrationsOfASpringMassDamperSystem/]]>http://demonstrations.wolfram.com/FreeVibrationsOfASpringMassDamperSystem/