The Ejs Orbiting Mass on a Table 3D model displays the frictionless dynamics of two masses that are attached via a string through a hole in a horizontal table.  Mass m moves on the table in two dimensions while mass M hangs vertically and just moves up and down.  The simulation allows displaying the motion of the masses as well as the effective potential energy.  The ratio of the masses, the total energy of the system, and the initial radial position of the mass on the table can be changed via textboxes.  A description of the system and example student activities are provided. 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 Orbiting Mass on a Table 3D 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_table.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).