The game of pool involves a total of 16 balls that can either be solid or striped colored. The game is often played by two or four players and each of the players are given long sticks. The sticks are used to hit all the balls into each of the pockets, at each side of the table. In order to win, the remaining players must hit the 8 balls into one of the pocket to end of the game. But how does this game relate to physics?

When we go out to play pool, many of us don’t realize how physics affects the game. If we stop and take the time to understand the basics of physics, it is amazing to see the degree we could improve our skills. The physics behind billiards (pool), in a larger image, involves collisions between two billiard balls. When two billiard balls collide the collision is called elastic. The definition of elastic collision is, “A collision in which colliding objects rebound without lasting deformation or the generation of heat.” People can assume that for collisions involving billiard balls, the collision will be completely elastic.

For collisions involving the two billiard balls, the momentum will always be conserved. The definition of momentum is, “The mass multiplied by its velocity.” In a collision with another billiard ball, the balls both exert a force on each other called impulse. This is similar to Newton’s Third Law of Physics, which says that, “The forces things exert on each other are always equal in strength and opposite in direction.” This also means that the impulse is equal and opposite. The connection between impulse and momentum is that impulse equals the change in momentum of each ball. If the change is similar to each other, the change in the total momentum must equal zero. If the change in total momentum is zero, then the total momentum must be the same before and after the collision. This concept is called the conservation of momentum.

In an example, let’s say you’re trying to hit the 8 ball in the corner pocket. Once you hit the cue ball, its momentum will be the mass times velocity. The momentum of the 8 ball is zero because it is not moving yet. If you hit it straight on and the cue ball stops before having a collision, then all of momentum of the cue ball goes into the 8 balls, because the momentum is conserved. If you hit it at an angle, both billiard balls will keep moving after the collision. If you add the momentum of the balls together, it will equal the momentum of the cue ball before the collision happens. The 8 ball travels at an opposite angle from the direction you hit it in, so you can always direct where you want the ball to go, if you hit it at a correct angle.

Understanding how conservation of momentum and collisions work will probably be helpful for your pool game to some extent. But, there are some complications we haven’t mentioned. When playing pool, you have to take into account that the balls might be sliding, rolling, or spinning. In addition, you have to worry about friction and irregularities in the pool table surface. In the end, if you sit down and try to calculate what would happen when you hit the cue ball, you would find yourself in a difficult problem.

Source by Alexander S Lee