The result of a football mach depends on more than just luck or the promise made to a saint. When scoring a goal or avoiding it is crucial, knowing the physical laws can help.

• Dribbling

You must understand what is law of inertia, developed by Galileo, to understand the dribbling: a moving body tends to remain in motion, and the Force is resulted of mass x acceleration (F = m x a). The lighter the player performing the dribbling is, the bigger his acceleration is and the easier it will be to overcome the bigger players, who require more strenght to move quickly to prevent the dribbling.

• Penalty

Kicking a penalty perfectly, or defending one, depends a lot in the player’s speed and reaction time.

In an official macth, goalkeeper must defend a total area of 17,86 m². The penalty mark is located 11 m from the goal (at the nearest point). On a penalty shot, the ball takes less than 0,5 seconds to travel that distance. And the goalkeeper has from 0,44 to 0,46 seconds to react to this shot. That’s why is almost impossible for him to wait for the move and then to choose which side to jump to. The goalkeeper needs to use this experience, as well as bit of luck, to know for which side the ball will be kicked and jump in advance. However, a study that analysed hundreds of penalties kicks in European championships noted that the best strategy is to remain in the center of the goal. But the reaction time makes goalkeepers prefer to anticipate the move than to take a risk remaining in the center of goal.

In football, there is the indefensable penalty. To perform this move, the player must hit the ball at the angle (difficult) at a speed of 104 km/h (even harder). In the center of goal, with this speed, it is impossible for a goalkeeper to move in time to catch the ball.

• Free kick

In a free kick, the player aims to kick the ball in a way so that it takes a curved course, straying from the barrier of players between the free kick mark and the goal. Backing to law of inertia, an object in uniform rectilinear motion tends to remain in this motion. To make a curved motion, a Force needs to interact with the velocity vector of the ball, in this case the force of gravity. This behavior of curve motion is called the Magnus Effect: when a cylindrical object (the ball) rotates on its own axis while in motion, the airflow is faster in its direction of rotation than in the opposite direction resulting in a curved motion, and the longer the distance to be traveled, the more kinetic energy is lost and the bigger the curved effect caused by the force of gravity acting on the ball will be. To perform this move, the player must kick “slightly” the ball with the internal part of the foot, so it can rotate, and hardly, so it can reaches the speed necessary for the Magnus Effect occurs.

These are just a few ways in which physics acts in the main moves of football.