Coulomb's Law and Electric Field Package Applet Page
Coulomb's Law and Electric Field Package: Dipole Trajectory Applet
The EJS Dipole Trajectory model shows the electric field generated by a dipole. A slider can change the separation between the charges. A test charge, with an adjustable initial position, is released from rest in the electric field.
*Recall that a test charge is defined to feel the effects of an external electric field, but not change the field itself (therefore, there are no field vectors around it).
The Dipole Trajectory Model was created by Anne J Cox, Wolfgang Christian, and Francisco Esquembre using the Easy Java Simulations (EJS) authoring and modeling tool. Exercises written by Anne J Cox.
You can examine and modify a compiled EJS model if you run the program by double clicking on the model's jar file. Right-click within the running program and select "Open EJS Model" from the pop-up menu to copy the model's XML description into EJS. You must, of course, have EJS installed on your computer.
Information about EJS is available at http://www.um.es/fem/Ejs/.