## How are volleyball and physics related?

What on Earth could volleyball and physics possibly have in common? Watching or playing a volleyballl game is an excellent way to see the principles of physics in action. Understanding physics can be tricky when you're just looking at a bunch of equations in a book. But by paying attention to the physics of sports like volleyball, those concepts become easier to grasp. Further, the athlete who understands the physics of the game has a definite advantage on the court. Here are a few of the basic principles of physics, explained through volleyball.

## GRAVITY

Gravitational force, or the force of attraction between an object and the Earth, has an impact on every element of Volleyball. Whether you are serving, bumping, or spiking, gravity will affect every interaction you have with the ball.

Serving: When a volleyball is served, the server exerts an upward, and forward, force on the ball. Meanwhile, gravity is exerting a downward force on the volleyball. This downward force is what causes the ball to fall down on the opponent's side, after clearing the net. To assist gravity, you can snap your wrist which adds top spin the skids over the ball as you serve. This spin crates pressure difference above and below the ball. According to researcher Dr. Marion Alexander, this top spin causes the ball to fall quickly on the opponent's side after clearing the net.

Passing: When a player performs a forearm pass, or bump, an upward and forward force is exerted on the ball toward a target player. Gravity exerts a downward force on the ball, and if you do not compensate for this, your target player will not have time to set underneath the ball before it hits the ground. To account for the force of gravity, simply follow through with your forearm when bumping, to exert force on the ball, over a longer period of time. This will cause the ball to go higher and ensure that the target player has time to prepare herself beneath the ball.

Spiking: When you spike a volleyball, you have the opportunity to deliver a crushing offensive blow to your opponent. When spiking, you exert a downward force on the ball so that it falls rapidly on the opponent's side of the court, making it very difficult for your opponent to return the ball. Gravity works in your favor when you spike, because it also exerts a downward force that makes the ball fall to the court floor. For this reason you do not necessarily have to exert tremendous downward force to spike effectively, because gravitational force is also acting on the ball in the same direction.

Digging: When digging a volleyball, you are exerting a sharply upward force to prevent it from hitting the ground. However, gravity is exerting a downward force on the ball, and if you do not account for this you will not hit the ball high enough to prevent it from hitting the ground. To account for this, bend your knees low to generate force with your legs, when digging. This will ensure that you hit the ball high enough for your teammates to get in position.

Serving: When a volleyball is served, the server exerts an upward, and forward, force on the ball. Meanwhile, gravity is exerting a downward force on the volleyball. This downward force is what causes the ball to fall down on the opponent's side, after clearing the net. To assist gravity, you can snap your wrist which adds top spin the skids over the ball as you serve. This spin crates pressure difference above and below the ball. According to researcher Dr. Marion Alexander, this top spin causes the ball to fall quickly on the opponent's side after clearing the net.

Passing: When a player performs a forearm pass, or bump, an upward and forward force is exerted on the ball toward a target player. Gravity exerts a downward force on the ball, and if you do not compensate for this, your target player will not have time to set underneath the ball before it hits the ground. To account for the force of gravity, simply follow through with your forearm when bumping, to exert force on the ball, over a longer period of time. This will cause the ball to go higher and ensure that the target player has time to prepare herself beneath the ball.

Spiking: When you spike a volleyball, you have the opportunity to deliver a crushing offensive blow to your opponent. When spiking, you exert a downward force on the ball so that it falls rapidly on the opponent's side of the court, making it very difficult for your opponent to return the ball. Gravity works in your favor when you spike, because it also exerts a downward force that makes the ball fall to the court floor. For this reason you do not necessarily have to exert tremendous downward force to spike effectively, because gravitational force is also acting on the ball in the same direction.

Digging: When digging a volleyball, you are exerting a sharply upward force to prevent it from hitting the ground. However, gravity is exerting a downward force on the ball, and if you do not account for this you will not hit the ball high enough to prevent it from hitting the ground. To account for this, bend your knees low to generate force with your legs, when digging. This will ensure that you hit the ball high enough for your teammates to get in position.

## Work, velocity, and acceleration

Work: Work is when a force moves an object. In Volleyball, the force is the player and the object is the ball. When the player hits, spikes, or serves the ball it moves in the direction in which the force has been applied. Hopefully, that direction will be over the net, when spiking or serving, and to the target when bumping.

Velocity: Velocity is the speed of movement. You can figure out the velocity of a volleyball shot by dividing the distance your ball traveled by the amount of time it took to get there. So let's say you serve a ball across the net from the behind the serving line, 30 feet, and the ball takes 1.5 seconds to get across the net. To find the velocity you would divide 30 feet by 1.5 seconds, which would be 20 fps. So the speed of movement, or velocity, of your serve was 20 feet per second. The higher the velocity the tougher it is for your opponent to hit the ball back to you. Which means, the faster your ball is traveling the harder it is to return.

Acceleration: Acceleration is an increase in velocity. Let's say you've just served the ball, it's gone over the net, and is falling to the ground. As gravity pulls the ball to the ground, it accelerates. If you gently lob the ball over the net and your opponent sends a hard spike back at you, that's another example of acceleration. The ball's velocity increased when spiked back over the net, by your opponent, therefore it accelerated.

Velocity: Velocity is the speed of movement. You can figure out the velocity of a volleyball shot by dividing the distance your ball traveled by the amount of time it took to get there. So let's say you serve a ball across the net from the behind the serving line, 30 feet, and the ball takes 1.5 seconds to get across the net. To find the velocity you would divide 30 feet by 1.5 seconds, which would be 20 fps. So the speed of movement, or velocity, of your serve was 20 feet per second. The higher the velocity the tougher it is for your opponent to hit the ball back to you. Which means, the faster your ball is traveling the harder it is to return.

Acceleration: Acceleration is an increase in velocity. Let's say you've just served the ball, it's gone over the net, and is falling to the ground. As gravity pulls the ball to the ground, it accelerates. If you gently lob the ball over the net and your opponent sends a hard spike back at you, that's another example of acceleration. The ball's velocity increased when spiked back over the net, by your opponent, therefore it accelerated.

## Newton's three laws of motion

Sir Isaac Newton, is said to be, the greatest English mathematicians of his generation. He laid the foundation for differential and integral calculus. His work on optics and gravitation make him one of the greatest scientists the world has known. Newton's laws of motion are three physical laws that form the basis for classical mechanics, and describe the relationship between the forces acting on the body and its motion due to these forces. Newton's laws affect every aspect of our life, therefore they affect volleyball, and every other sport, greatly. I'm going to inform you on just how the laws do affect volleyball.

Newton's first law states that, " An object at rest will stay at rest, and an object in motion will stay in motion unless acted upon by an unbalanced force."

How does this affect Volleyball? : Newton's first law of motion affects every volleyball player who botches a serve and sends the ball snacking into the net. Every player who blocks a hard-hit ball from an opposing player feels the law's effect on her stinging arms. The server's hand, the net, and the blocker's forearms acted as an unbalanced force that stopped, or changed, the direction of the ball, the object in motion.

Newton's second law states that, " The acceleration of an object is directly proportional to the net external force acting on the object and inversely proportional to the mass of the object."

How does this relate to Volleyball? : Newton's second law of motion is a mathematical equation that explains the relationship between force, mass, and acceleration. Mass multiplied by acceleration equals net external force. A spiked volleyball creates a net external force that stings your hands when you stop it. But your hands hurt even more when you stop a ball hit by a different, stronger opponent. The harder-hit ball's higher acceleration rate results in a stronger net external force.

Newton's third law states that, " To every action there is an equal and opposite reaction."

How does this relate to Volleyball? : Newton's third law explains that every action creates a force that is met by an equal reaction force from the opposite direction. When two objects interact, they exert a force on each other. The action force of a spiked ball meets the reaction force of a player's block. A team scores a point when the action force of a spiked ball meets the reaction force of the opposing team's court. The hard floor has more force than the soft ball, so the ball bounces off the court to equalize the reaction of the impact.

Newton's first law states that, " An object at rest will stay at rest, and an object in motion will stay in motion unless acted upon by an unbalanced force."

How does this affect Volleyball? : Newton's first law of motion affects every volleyball player who botches a serve and sends the ball snacking into the net. Every player who blocks a hard-hit ball from an opposing player feels the law's effect on her stinging arms. The server's hand, the net, and the blocker's forearms acted as an unbalanced force that stopped, or changed, the direction of the ball, the object in motion.

Newton's second law states that, " The acceleration of an object is directly proportional to the net external force acting on the object and inversely proportional to the mass of the object."

How does this relate to Volleyball? : Newton's second law of motion is a mathematical equation that explains the relationship between force, mass, and acceleration. Mass multiplied by acceleration equals net external force. A spiked volleyball creates a net external force that stings your hands when you stop it. But your hands hurt even more when you stop a ball hit by a different, stronger opponent. The harder-hit ball's higher acceleration rate results in a stronger net external force.

Newton's third law states that, " To every action there is an equal and opposite reaction."

How does this relate to Volleyball? : Newton's third law explains that every action creates a force that is met by an equal reaction force from the opposite direction. When two objects interact, they exert a force on each other. The action force of a spiked ball meets the reaction force of a player's block. A team scores a point when the action force of a spiked ball meets the reaction force of the opposing team's court. The hard floor has more force than the soft ball, so the ball bounces off the court to equalize the reaction of the impact.

The next time you're playing or watching a game of Volleyball, think about all of the elements of physics involved. Without gravity, acceleration, velocity, work, and Newton's laws, Volleyball wouldn't be challenging at all.