Physics of soccer

Topics  Newton's Laws of physics  Mass  Velocity  Acceleration  Inertia  Momentum  Kinetic Energy  Potential Energy  Gravity

Definitions  ACCELERATION - change in velocity divided by the time interval over which it occurred, acceleration is positive if the velocity change is positive. a = v/t  GRAVITY - affects weight (acceleration due to gravity) (g), a vector quantity having both magnitude and direction, a freely falling object has an acceleration of -9.8 m/s^2

 VELOCITY - ratio of change in position to time interval over which change takes place, includes speed and the algebraic sign or direction, it can be negative or positive, measured in meters per second (m/s). v = d/t  WEIGHT - measured in Newton's (N), force of gravity on an object, depends on the acceleration due to gravity.

 MASS - measured in kilograms (kg), amount of matter an object contains, mass is constant for any object.  MOMENTUM - product of object's mass and velocity, vector quantity that has the same direction as the velocity of the object, measured in kilogram meter per second. (kg-m/s) p = mv

Newton's First Law  Newton's first law states that an object in motion will remain in motion unless acted upon by an outside force; an object at rest will stay at rest unless acted upon by an outside force.

Mass  When force is applied to the ball it is accelerated into motion, but also mass of the ball counts. The mass of a ball is probable 400 grams. Also with out gravity the ball would stay in the air forever and drag.

Inertia  Inertia = property of mass and it cannot change. The ball has very little inertia because it is small so it is easy to stop it once it is moving. A small net force is required to change its speed.

Energy's and momentum  When you kick a soccer ball you are using energy, both potential and kinetic. As the player's foot accelerates into the ball, two laws come into effect: The conservation of energy and the conservation of angular momentum. If no energy was let off, the speed of the ball would be exactly twice that of the foot.  The ball is struck as close to the leg’s maximum velocity as possible – so really, the ball “bounces” off of the moving foot for a finite distance. The momentum of the foot goes into the ball, giving the ball a velocity.

Newton's Second Law Newton's second law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This can be very easily be stated using the equation: F=ma. In this case F is the net force, m is the mass of the object, and a is the acceleration of the object. accelerationnet force

 This can be seen when you kick the ball, the more force you use to move the ball the greater the acceleration of the ball. So the greater the mass the more force it will take.

Newton's third law  Newton's Third Law of Motion states that for every action there is a an equal and opposite reaction. Newton's Third Law of Motion

 Every time you go to kick the ball this law comes into effect. You may not realize this because we are so massive compared to the ball that we do not realize that the ball actually pushes back on our foot as we push against it.

Sources   /newtonsthreelaws/section1.html Date: 10/18/o8 This sources really help me a lot to better understand physics. To tell you the truth it really bothers me that I got this stuck in my head, now when I play soccer I will always think of physics.

Painful /funny soccer