Lift, Drag, and Rotation

    When a Frisbee is thrown the disk glides through the air in a horizontal motion and spins around its axis. This occurs because of three concepts which are known in Physics as lift, drag, and rotation.

Lift:

~http://www.exploratorium.edu/

    Lift is the force perpendicular to the direction of motion though air. Lift is created when air flows faster over an object than below. This occurs when the edge of an object is curved allowing for the air to move quicker over the top than the bottom. This is what allows a Frisbee to glide longer distances than a flat object of the same dimensions. Lift can be explained by the Bernoulli principle. Bernoulli's principle states that when air moves at a higher speed the air has a lower pressure and when air moves at a lower speed air has a higher pressure. Lift acts on the bottom edge of the disk and not the center.

Drag:

   In the case of the Frisbee drag is the force opposite of the direction of motion created by air resisting the Frisbee. Unlike most objects the Frisbee is disk shaped and somewhat flat. Most of the Frisbee's surface is on the top and bottom. Because of this the air resists less of the Frisbee and results in less drag.

~https://www.scientificamerican.com

Rotation:

   Rotation is the force that keeps the Frisbee horizontal during its flight. Because lift acts on the bottom edge of the disk the disk would flip without rotating. The reason the disk does not flip while rotating is because of a scientific principle called gyroscopic motion. At each point in time the disk is wanting to flip at the point that the lift is acting on it. As the Frisbee spins the direction that the disk wants to flip changes. This happens at every point as the disk spins all the way around. Because of this the disk is always counteracting the lift from flipping the disk. Drag also plays a part in the disk not flipping. At each point in time during the rotation the air is flowing over the top and bottom of the disk keeping it from wobbling.