I played soccer for about 3 years, and never understood that physics applies to all aspects of the sport, as it does to every sport. For example, kicking the ball into the air is an example of projectile motion. The ball is launched at a certain angle above the ground, or the horizontal, and lands back on the ground. During this entire time, the ball is being acted upon by gravity, causing the acceleration to be 9.81 m/s^2. Also, when the ball reaches it's maximum height, its velocity is 0 m/s. Lastly, Newton's 1st Law states that an object at rest stays at rest, and an object in motion stays in motion in a straight line at constant velocity, unless acted upon by a net force. This law applies to soccer, because when a ball is kicked but does not leave the ground, its velocity decreases as the time and distance increase, because it is being acted upon by friction, a net force.