The Ejs Three Charged Particles model displays up three charged objects, one at each corner of an equilateral triangle. The charges have different magnitudes - your job is to rank the charges based on their magnitudes, from largest to smallest.  You can drag the charges around to see the effect on the net force on each charge.  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 Three Charged Particles 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_bu_three_charges.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).