This applet simulates motion along a constrained path, such as a roller coaster would take (assuming it has safety wheels to keep it on the track in “up-side-down” situations, of course). The simulation offers a chance to explore a number of concepts associated with roller coaster physics, including conservation of energy, reaction forces and motion in a vertical plane. There are a number of example tracks which can be accessed via the drop down menu on the bottom right. The speed of the simulation can be modified by changing the calculation time step dt. recommended dt = 0.01 for accuracy results, dt = 0.05 is faster but may have computational error.
my source with the other files for the graphics are attached as the 2nd attachment, cos download the source file alone is not able to recreate the graphics of the roller coaster so use the zip for remixing, saved it into your EJS source folder
Michael Gallis is the original creator, i only remixed it, refined it and fixed some bugs in the drop down menu