The Physics of Soccer - Introduction
Physics is the branch of science that deals with the physical world and its properties.
Physics use math to explain the behavior of matter as we observe it with the naked eye.
Soccer physics explain why the soccer ball curves, why the ball bounces and how high it bounces as well as how the pressure in the ball affects the bounce or kick of the ball.
To better explain physics in soccer we need to use some of the physics laws such are:
Newton's law of motion, Bernoulli's discoveries about fluid flow, Maxwell's equations of electromagnetics, Einstein's theories of gravitation and relativistic motion, and a lot more complicated formulas and physics laws.
Just kicking the soccer ball relates to the physics of motion, the physic of friction, and even aerodynamics.
Newton's 1st law
The first law of motion is called the Law of Inertia.
It states that “any object at rest, will tend to stay at rest, and any object in motion, will tend to stay in motion unless acted on by an unbalanced force.”
This unbalanced force could be: gravity, wind, or any moving object.
In the physics of soccer unbalanced force is usually the player’s foot.
The player will use muscle in the body to create a force to move the leg and kick the ball.
Because the ball is at rest, it will continue to stay at rest but once kicked, it will keep moving in a straight line without any intent of stopping because of the physics of soccer.
The reason for the ball stopping is because of friction and Earth’s gravitational pull.
Newton's 2nd law
Newton’s second law states that “The change in velocity (acceleration) with which an object moves is directly proportional to the magnitude of the force applied to the object and inversely proportional to the mass of the object.”
Using the physics of soccer this simply means that if the ball has a lot of mass, it will require more force to accelerate and if the ball has little mass, it will require very little force to accelerate when the soccer ball is kicked.
Newton's 3rd law
Newton’s final law of motion states that “for every action, there is an equal and opposite reaction.”
This literally means that if you kick the soccer ball, it will kick back at you just as hard.
The only reason you don't feel or realize this, is because our legs have more mass, meaning more inertia, which is the resistance to move according to the physics of soccer.
The physics of soccer continue with Momentum.
Momentum is the velocity of object times its mass.
Every time we strike the soccer ball we transfer the momentum to the ball.
Also whenever we receive the soccer ball we use our feet to slow down the momentum of the ball by moving our feet back and resisting the ball slowly so that we have more control of the ball.
It is very exciting to see a player score a goal by bending the soccer ball around the players and into the back of the net.
So how are players able to do this?
Physics on a soccer ball is the best way to explain how this happens.
Soccer ball is basically a projectile that is flying through the air because of velocity provided to it by kicking the ball.
Reason for the ball curving is because the player kicks the ball at a certain angle and with certain velocity (power).
Once the ball is kicked and is flying through the air, its really the air that is curving the ball.
The Magnus affect is the reason the ball curves through the air.
Once the ball’s velocity drops the Magnus affect will start to increase.
When a ball spins through fluid matter, it creates a barrier of air, kind of like a force field making the ball travel with just enough speed to cause the soccer ball to curve in the air tricking the goalkeeper as its moving through the air with a curve.
This affect will make the ball travel with just fast enough speed so it curves in the air to trick and beat the goalkeeper :)
Drag occurs when the soccer ball is kicked and it travels through the air pushing through while the air pushes back, thus slowing the soccer ball down according to the physics of soccer.
Drag is the reason that soccer ball doesn't travel in a perfect parabola.
Drag can be dramatically decreased by kicking the soccer ball with a spin and once the ball starts spinning it causes magnus effect which decreases air resistance drastically.
Whenever the soccer ball is kicked on the ground there is always a force parallel, but opposite of the soccer ball according to soccer physics.
This parallel and opposite force is called friction.
Friction is caused when two opposing surfaces make contact with each other.
The electromagnetic forces within each surfaces resist the relative lateral motion of objects, in this case it is the soccer ball and grass.
Friction can also happen when the ball is in the air.
Because air is matter, friction is always present.
Friction is the reason why the soccer ball always slows down.
People sometimes confuse gravity as the force that slows down the soccer ball, but the physics of soccer prove that gravity is really just increasing the friction because it forces the ball down against the ground and when that happens friction occurs.
Friction turns kinetic energy into heat so if you can kick the ball hard enough , the soccer ball can actually catch on fire :D
Projectile motion is best shown when the ball is kicked by the soccer player and it reaches its maximum height before it comes back down.
When the ball reaches the very top height, the velocity is equal to zero.
The reason why the ball did not go straight upward when it was kicked but instead comes back down on the ground is because the ball is being pulled down by earth's gravity.
With this knowledge of soccer physics, you can now understand how soccer works and why it works that way.
Use this knowledge to improve your game :)
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