© Dr. Steve Rapp, 2004

Elastic Collisions

uA vector diagram shows
the momenta of the balls before and after collision.

MbV’b

MrV’r

MbVb

Since the masses are equal Vb2 = V’b2 + V’r2.

When two balls of equal mass strike one another

(one is at rest), the two balls move away from one

another at right angles.