The Ejs Spinning Dumbbell model displays the motion of a dumbbell spinning around the fixed vertical axis z with constant angular velocity.  The trajectories of each mass as well as the system's angular velocity, angular momentum and applied toque can be shown.  The angle between the rod and the vertical, and the angular speed can be changed via textboxes.  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 Spinning Dumbbell 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_rigid_bodies_dumbbell.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 rigid body dynamics 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).