The Physics of Basketball

Basketball, and proficiency in basketball, has a great deal to do with physics whether the player knows it or not. The game is played with two opposing teams of five players each. The object of the game is to move a ball, by dribbling it across the court, to a ten foot high basket. This can be done in three ways: dribbling the ball down court, passing the ball between different players down court, or a combination of the two. At the basket, the player can throw the ball into the basket to attempt to score the point. If the shot is successful, the team with the player that made the successful shot gets two points. If the shot misses the basket, all members of either team are allowed to try to pick it up and score a point for their team themselves. Physics plays a principle role in three areas of the game: shooting the ball into the basket, bouncing the ball, and receiving a pass. (The Physics of Basketball)

Physics plays a major role in shooting a basketball which is an example of nonlinear motion. The ball follows the same pattern of other objects in projectile motion. Gravity pulls the ball rising up from the player’s hands to fall in an arc toward the basket. Using the laws of projectile motion, we can assume that the time it takes to go up equal to the time it takes to fall into the basket (or fall somewhere near the basket). Raising the height at which the ball is thrown toward the basket can increase the percentage at which the shot is made. For example, the definitive study on the physics of basket ball, done in 1981 by Peter Brancasio, found that if the height at which a ball was shot was raised by .61 m, the successful shot percentage would increase remarkably by 17%.

There is a negligible amount of energy lost during the shot due to air resistance, so the player does not have to compensate for this loss; however, as the distance of the shot, from the shooter to the basket, grows greater, there is more of a chance this will affect the shot. A backspin on the ball when shooting is useful during the shot because it gives the shooter a better probability of the ball going in. With a spin on the ball, a greater amount of energy is transferred from the ball to the basket and the rim through friction. If the player lessens the amount of energy in the ball when it hits the rim, the ball is less likely to bounce off the basket and the rim. Instead it will allow a greater chance that the ball will roll into the basket. (Kent K-12)

When the ball is dribbled, it contacts with the court’s surface creating an opposite reaction causing the ball to fly back up into the dribbler’s hand. Energy lost in this reaction is due to friction on the courts surface and the dribbler’s hand, air resistance, and the transfer of heat to the court’s surface. A ball loses 38% of its energy in each bounce, so to dribble effectively, the player must put that amount of energy or more back into the ball. (Why does a basketball bounce higher when it has more air in it?)

The ball’s air pressure affects its performance in the game. A full pressure ball is less likely to bounce erratically or deflate when dribbled. “Air stores and returns energy more efficiently than the material the ball is made from,” according to The Science Files: Physics of Basketball. Therefore, a well inflated ball will loose less energy as it bounces as compared will a flat ball. Also, if a ball is not inflated properly, it will not pass or rebound well.

The force of a hard pass can be lessened using the equation M x V = F x T where M equals mass, V equals velocity, F equals force, and T equals time. Thus, momentum can be measured as M x V . The equation can be changed to find F: (M xV)/T = F. This makes it easy to see that if the player can increase the time it takes to decelerate the ball, it will results in lower amount of force from the pass. (Physics of basketball)

Though Physics is constantly present in the sport, a player cannot be expected to rely on math equations and precise mathematical movements in order to perfect his or her game. Also, a player cannot possibly calculate the precise angle and speed at which the ball must be acted upon to achieve a desired result in a matter of seconds; therefore, players must rely on trial-and-error, and muscle memory (kinesthetic memory) in order to raise their shot percentage

“Physics of Sports”. Physics of Sports Teacher’s Guide.

“Physics of Basketball”. Kent K-12.

“Physics of basketball”. University of Toronto.

“The Physics of Basketball”. Geocities.

“Why does a basketball bounce higher when it has more air in it?”. Physics Central.