Final answer:
The forces exerted by the soccer player's foot and the ball do not cancel out because they act on different systems: the player's foot on the ball and the ball on the player's foot.
Step-by-step explanation:
When a soccer player kicks a ball, Newton's third law of motion comes into play. Newton's third law of motion states that whenever one body exerts a force on a second body, the first body experiences a force that is equal in magnitude and opposite in direction to the force that it exerts. While these forces are equal and opposite, they do not cancel each other out because they are acting on different systems. In the case of the soccer player and the ball, the force exerted by the player's foot on the ball acts on the ball, accelerating it forward, while the force exerted by the ball on the player's foot acts on the player and not on the ball; this does not affect the ball's movement.
A soccer ball being kicked is subject to various forces such as gravity, air resistance, and friction, in addition to the force of the kick. However, when considering the movement of the ball after the kick, the force from the foot is the external force contributing to the ball's acceleration, separate from the force the ball exerts back on the foot.