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 http://www.phy.ntnu.edu.tw/ 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