Physics of Pool

The game of pool actually involves a lot of physics! Although they may not know them, good pool players implicitly understand the law of conservation of energy, and the law of conservation of momentum. Because the cue ball does not stick to the ball it hits, all the collisions in pool are elastic, which means that both kinetic energy and momentum are conserved. For example, if you shoot the cue ball horizontally and hit the side of a ball, they will veer off in different directions. If you calculated the y component of momentum for each ball, they would be equal and opposite so that the final momentum in the y direction is equal to the initial y momentum of the shot (which is zero, because you are shooting the cue ball horizontally). This is true because of the law of conservation of momentum. If the head on collision was truly perfectly elastic, the v final (velocity of the second ball) would equal the v initial (velocity of the cue ball), but due to friction and air resistance, the velocity of the second ball is slightly less than the velocity of the cue ball before the collision. Therefore, to be a good pool player, one must first have a solid understanding of the fundamentals of physics!