The Ejs Inertial Oscillation model displays the motion of a particle moving over the surface of an oblate spheroid. The spheroid is flattened to an ellipsoid of revolution because it is rotating, just as the Earth is flattened because it is rotating. The particle is confined to motion along the surface by the spheroid's gravity; the motion parallel to the surface is treated as frictionless.  The simulation shows simultaneously the motion with respect to the inertial coordinate system, and the motion as seen from a co-rotating point of view. For the co-rotating view the user can switch between a close-up view and an overview.  A brief, but complete, mathematical discussion of this simulation is available at:
http://www.cleonis.nl/physics/ejs/inertial_oscillation_sim_ext.php.  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 Inertial Oscillation 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_nl_teunissen_InertialOscillation.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 classical mechanics are available.  They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs, or by visiting the author's web site: http://www.cleonis.nl/index.htm.

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