Does the following applet similar to what you want?

The potential is 1/R and it was designed to show trajectory in potential well and real tractory in space coordinate.

/htdocs/ntnujava/ejsuser/2/users/ntnu/fkh/oneoverR_pkg/oneoverR.propertiesFull screen applet or Problem viewing java?Add to exception site list
Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop. This work is licensed under a Creative Commons Attribution 2.5 Taiwan License
Download EJS jar file(1314.1kB):double click downloaded file to run it. (54 times by 30 users) , Download EJS source (13 times by 9 users) View EJS source