For Pi Day, Calculate Pi Yourself Using Two Colliding Balls | WIRED
Chapter 7, Example #9 - Two dimensional elastic collision of billiard balls - YouTube
Newton s cradle , but in the real world of billiards there is an additional force on each ball due to friction with the table. The effect of friction can be seen by observing the ball that is initially at rest (by advancing the film one frame at a time). After the collision it ...