When the two balls collide with each other, some of the upward motion of the lower ball is transferred to the upper one.

When the balls collide, momentum from each ball can be transferred to the other.

Due to no air resistance and energy lost in the form of sound when the balls collide.

Sometimes the balls return and collide again.

The maneuver seemed simple enough, a quick reciprocal toss, but when Valentine tried it the balls collided and went bounding away.

The heavy ball collides with Sylvester - and he swallows it!

But the ball collided with the right shoulder of Loverne, who was running straight ahead.

The ball collided forcefully with a billboard just below the black seats.

The way things were going, Jeter said, he wondered if his ball would collide with a bird and land in an outfielder's glove.

The balls could split up and collide until they reached the bottom of the track and crossed the finish line.