The EJS Coulomb's Law and Electric Field Package is a collection of models for electrostatics. You can move charges around and see the force, you can observe the electric field generated by charge configurations and observe the motion of test particles in electric fields. You can inspect and modify any simulation in the package if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item.
EJS Coulombs Law and Electric Field Package
Quelle: Open Source Physics