Physics of soccer

YouTube Video

Avery Shelton, Connor Kennedy, Dave Robell, Matt Polly


For our physics of sports project we decided to analyze the physics of kicking a soccer ball. We needed to determine the force, velocity, acceleration, momentum, and impulse to find the physics of a penalty kick. This would help determine a goalies reaction time as well as the force and speed of a soccer ball.  We calculated the force to be 8.99 newtons, the average velocity to be 12.55 m/s sq, the acceleration to be 20.92 m/s sq, momentum to be   5.4 kg* m/s  and impulse to be 5.39 .  

v= d/t       7.53/.60  v=12.55

f=ma f=.43 * 20.92 = 8.99 

A = vf-vi /t         a=12.55-0 / .60    a=20.92

p=mv   12.55 * .43 p= 5.4 

Impulse= ft    8.99 * .60  I=5.39

Work=fd  8.99*1.15= 10.34

 Velocity         12.55 m/s sq
 Force              8.99 Newtons
 Acceleration 20.92 m/s sq
 Momentum  5.4 kg*m/s
 Work 10.34

Average Acceleration is the change in velocity over time. As the ball moves away from its starting point and slows down  the acceleration decreases and  drastically changes.

Average Velocity: This chart shows the rate of change in distance, or displacement. As the bal moves away from the kicker’s feet and towards the goal, the ball speeds up which causes the graph to move up and down. After .5 seconds, the ball begins slowing down. 

Momentum: Momentum is the product of mass and velocity. Because the soccer ball’s mass does not change, it’s velocity causes the change in momentum shown on this chart.

Time/Distance: This chart shows the change in time and distances or the final velocity.

Rotation angle: shows the movement of an object in a circular motion. As the soccer ball moves forward, it is bound to spin.  This graph shows the balls spin as it moves towards the goal.

Work: Work equals force times the distance of the things doing the work, in this case Connor's leg. Connor's leg is about 1.2 meters long, therefore work equals 1.2 times 8.99 equals work.

As you can see, the goalie completely missed the shot. point Connor. Connor's application of work and velocity helped him make this shot. Penalty kicks like this one are already difficult for the goalie to judge, because the ball is starting from rest. The extension of Connor's leg helped apply more force to the ball, because the follow through keeps contact with the ball until the last second. Had connor pulled his foot away earlier instead of extending it upward, the shot would've been less powerful. Angle and momentum are also important. The ball curves a bit upwards at the beginning, but stays mostly straight forward, avoiding any lag or loss of momentum on the ball. Because the balls velocity goes down as it travels so does its momentum which means it is important to kick the ball hard and fast without trying to pull any fancy tricks or curves. Basically Connor did the right thing by choosing a corner to shoot in and kicking, instead of trying to aim high and make the shot look pretty.