Math Player Demos
To play the Math Player Demos you must download the MathPlayer Program
This demonstration allows the user to manipulate the value of physically important variables in the system and the output is the motion of a pendulum as defined by the angular position of the pendulum bob relative to vertical.
The damped pendulum model is programmed in Mathematica by Olaf Ellers and is based on the math published by others in the following paper:
Neill D, Livelybrooks D & Donnelly R (2007). A pendulum experiment on added mass and the principle of equivalence. Am. J. Phys. 75(3): 226-229.
Neill et al. also provides an experimental test of the calculations.