Details

Description of the User Interface

Four buttons are used to control the Demonstration. You select the number of particles and the radius of the particles, and then click "run" to see the motion in 2D. All the particles have the same size. You can change the collision from elastic to inelastic using the slider for the coefficient of restitution. You can see the current position, speed, and mass of each particle as it moves by using the checkbox labeled "annotation".

Possible Issues

As this is not a real-time simulation, keeping the frame rate synchronized with the time of collision in order to achieve smooth motion all the time was difficult. The occasional jumps in motion can be reduced by keeping the simulation speed slow (i.e., keeping the simulation time step size small).

References

[1] David Morin, Introduction to Classical Mechanics: With Problems and Solutions, New York: Cambridge University Press, 2008.

[2] David Eberly, Game Physics, 2nd ed., New York: Morgan Kaufmann, 2010.

[3] Wikipedia. "Collision Detection." (Oct 21, 2012) en.wikipedia.org/wiki/Collision_detection.