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Collision Lab


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PhET Interactive Simulations
University of Colorado Boulder


  • Collisions
  • Momentum
  • Velocity


Use an air hockey table to investigate simple collisions in 1D and more complex collisions in 2D. Experiment with the number of discs, masses, and initial conditions. Vary the elasticity and see how the total momentum and kinetic energy changes during collisions.

Sample Learning Goals

  • Draw "before-and-after" pictures of collisions.
  • Construct momentum vector representations of "before-and-after" collisions.
  • Apply law of conservation of momentum to solve problems of collisions.
  • Explain why energy is not conserved and varies in some collisions.
  • Determine the change in mechanical energy in collisions of varying “elasticity”.
  • What does “elasticity” mean?
Version 2.01