Mechanics

# Kick x Thrust

Football is the most popular team sport in the world. Athletes active in this sport are objectified by scoring goals. The driving of the soccer ball happens, in great part of the game, through the contact between the feet of the players and the ball, this contact denominated as kick.

The kick given by the players is interpreted physically (in terms of the variation of momentum) by the relationship established between the force that he applies with the ball and the time that this force (time of contact between the player’s foot and the ball) takes place. acts on it; this relationship is called impulse.

The impulse applied to a ball will cause variation in its momentum, giving it greater or lesser speed.

In a free kick (ball at rest), consider that a player kicks the ball applying a force of magnitude 1.2. equivalent to 108km/h; see the calculations below.
F = 1.2.10²N
Δt = 0.1s
m = 400g = 0.4Kg
Vo = 0
V = ?
I = ΔQ
F.Δt = mV – m.Vo
1.2.10².0.1 = 0.4.V – 0
V = 12/0.4
V = 30m/s
V = 30.3.6 = 108Km/h
Initially we had the ball at rest, and after the kick the ball reaches a speed equivalent to 108 km/h (30m/s). Due to the impulse given to the ball by the athlete’s foot, the amount of movement of the ball was changed. We soon see that the kick is nothing more than Impulse.