The Ejs Pendulum Motion in Phase Space model displays the dynamics of an ensemble of pendula in phase space (velocity versus position).  Friction is set to zero.  For the pendulum ensemble, the motion is shown both in a traditional phase-space plot and on a phase-space cylinder which keeps the angular position between –pi and pi for large initial angular velocities.  You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item.  

Ejs Pendulum Motion in Phase Space model was created using the Easy Java Simulations (Ejs) modeling tool.  It is distributed as a ready-to-run (compiled) Java archive.  Double clicking the ejs_ehu_analytical_mechanics_pendulum.jar file will run the program if Java is installed.  Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models.  Additional Ejs models for Newtonian mechanics are available.  They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Please note that this resource requires at least version 1.5 of Java (JRE).