Elastic Collisions of Two Spheres

relative mass

1

impact parameter

0

time

reference frame

laboratory

center of mass

In an elastic collision, both momentum and kinetic energy are conserved. This Demonstration models collisions between two hard spheres of equal density. You can vary the relative mass and the impact parameter

b

, the distance of closest approach of the centers if the spheres are undeflected. For a head-on collision,

b=0

. You can observe the collision in slow motion in either the laboratory or the center-of-mass frame of reference. The spheres leave dotted contrails to help you trace their trajectories.