English: Billiard chalk is used to increase fricti...
English: Close-up picture of billiard balls
Various novelty pocket billiards balls. Clockwise ...The game of pool may not be as relaxing as one may think. Rather than just aimlessly hitting the cue ball around a table covered in felt, there is a set of law governing the outcome of play. These laws are known as PHYSICS. Billiards is played by striking the cue ball with a cue stick. The cue ball then collides with the other balls on the table in hopes of propelling one or more balls (preferably not the cue ball) into one of the six pockets. Based on the type, angle, and momentum of the collision, the ball will respond accordingly. A general rule of thumb for this game of angles is momentum = mass x velocity. The momentum of the cue ball before it strikes another ball will always be equal to the momentum of the cue ball and whatever it strikes afterward according to the conservation of momentum. So if the cue ball is moving quickly, there is a good chance the ball it hits will also move quickly; and just the opposite if the cue ball has a small velocity, or speed. Since momentum is a vector quantity, it describes both magnitude and direction. To truly conserve momentum, the direction of the balls resulting from the collision must also cancel out with the direction of the cue ball. The get a ball to go exactly where you want it, just calculate the angle desired, and strike the cue ball with the appropriate velocity. Who said physicists weren't up for sports?