Particle Motion Simulation Using A Priori Collision Detection

This Demonstration implements a physics collision detection device using a priori (continuous) collision detection to simulate the motion of particles in 2D. You can have up to six particles at the same time moving inside a closed unit square. Collisions between particles and the walls can be elastic or inelastic. The masses of the particles can be the same or different (randomly generated). No friction and gravity are neglected, hence the speed of the particles is the same after collisions.


  • [Snapshot]
  • [Snapshot]
  • [Snapshot]


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).
[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.
    • Share:

Embed Interactive Demonstration New!

Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site. More details »

Files require Wolfram CDF Player or Mathematica.

Mathematica »
The #1 tool for creating Demonstrations
and anything technical.
Wolfram|Alpha »
Explore anything with the first
computational knowledge engine.
MathWorld »
The web's most extensive
mathematics resource.
Course Assistant Apps »
An app for every course—
right in the palm of your hand.
Wolfram Blog »
Read our views on math,
science, and technology.
Computable Document Format »
The format that makes Demonstrations
(and any information) easy to share and
interact with.
STEM Initiative »
Programs & resources for
educators, schools & students.
Computerbasedmath.org »
Join the initiative for modernizing
math education.
Step-by-Step Solutions »
Walk through homework problems one step at a time, with hints to help along the way.
Wolfram Problem Generator »
Unlimited random practice problems and answers with built-in step-by-step solutions. Practice online or make a printable study sheet.
Wolfram Language »
Knowledge-based programming for everyone.
Powered by Wolfram Mathematica © 2017 Wolfram Demonstrations Project & Contributors  |  Terms of Use  |  Privacy Policy  |  RSS Give us your feedback
Note: To run this Demonstration you need Mathematica 7+ or the free Mathematica Player 7EX
Download or upgrade to Mathematica Player 7EX
I already have Mathematica Player or Mathematica 7+