A Special Case
An interesting, special case of an elastic collision is a one-dimensional collision in which one of the objects is initially at rest (v2i = 0).
These results can be described by the following equations for this special case:
An interesting situation is when the two masses are equal. For m1 = m2, we find that
v2f = v1i
This is illustrated with the "colliding balls" apparatus shown here, also known as "Newton's Pendulum".
Elastic Collisions Rocket Propulsion Return to ToC, Work and Energy (c) 2002, Doug Davis; all rights reserved