The Ejs Great Circles model displays the frictionless motion of a particle that is constrained to follow the surface of a perfect sphere.  The sphere rotates underneath the particle, but since there is no friction, and the sphere is perfectly spherical, the motion of the particle is not influenced by the sphere.  The simulation shows simultaneously the trajectory with respect to the inertial coordinate system, and the trajectory as seen from a point of view that is co-rotating with the sphere.  The particle remains co-rotating until the Release/Launch button is pressed. On pressing the Release/Launch button the particle commences to move along the great circle that is tangent to the initial latitude.  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 Great Circles 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_GreatCircles.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).