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the quarterback throws the football, it follows a path called a parabola . If we didn’t have gravity, the football would follow a straight line. When the quarterback releases the ball, the force causes it to travel up. The ball reaches the top of the parabola—the peak height—but gravity then pulls the ball downward as it travels in a vertical direction.

Because of Earth’s gravity, any object that is thrown or launched—a ball, an arrow, or even a missile—travels in a parabolic path. This is also

Several scientific principles are at work behind a completed pass.

referred to as projectile motion. The quarterback controls three factors of the throw: > The speed (velocity) at which he throws the ball > The angle of the throw > The rotation of the football

The speed of the throw will determine how long the ball will remain in the air and how far it will go. When throwing a football, the quarterback has to have arm strength to make the ball go farther and faster. When the ball leaves the quarterback’s hand, it moves with a speed that is determined by the force placed on the ball, and that comes from arm strength. The angle of the throw also matters. Remember your x-, y-, and z-axes from physics. The ball will move vertically and horizontally and will go a certain height in the air. The angle at which the quarterback throws the ball has an impact on the path the ball

CHAPTER 1 : THROWING

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