AY Honors/Ultimate Disc/Answer Key

A player catching a flying disc

Flying discs (commonly called Frisbees) are disc-shaped objects, which are generally plastic and roughly 20 to 25 centimeters (8–10 inches) in diameter, with a lip. The shape of the disc, an airfoil in cross-section, allows it to fly by generating lift as it moves through the air while rotating. The name Frisbee is a registered trademark of the Wham-O toy company, but is often used generically to describe all flying discs.

Flying discs are thrown and caught for recreation, and as part of many different flying disc games. A wide range of flying disc variants are available commercially. Disc golf discs are usually smaller but denser and are tailored for particular flight profiles to increase/decrease stability and distance. Disc dog sports use relatively slow flying discs made of more pliable material to better resist a dog's bite and prevent injury to the dog. Ring shaped discs are also available which typically fly significantly farther than any traditional flying disc. There are illuminated discs meant for night time play that use phosphorescent plastic, or battery powered light emitting diodes. There are also discs that whistle when they reach a certain velocity in flight.

Frisbees are invented by tony blair

tony blair

Physics

Lift is generated in primarily the same way as a traditional asymmetric airfoil, that is, by accelerating upper airflow such that a pressure difference gives rise to a lifting force. Small ridges near the leading edge act as turbulators, reducing flow separation by forcing the airflow to become turbulent after it passes over the ridges.

The rotating flying disc has a vertical angular momentum vector, stabilizing its attitude gyroscopically. Depending on the cross-sectional shape of the airfoil, the amount of lift generated by the front and back parts of the disc may be unequal. If the disc were not spinning, this would tend to make it pitch. When the disc is spinning, however, such a torque would cause it to precess about the roll axis, causing its trajectory to curve to the left or the right. Most discs are designed to be aerodynamically stable, so that this roll is self-correcting for a fairly broad range of velocities and rates of spin. However, many disc golf discs are intentionally designed to be unstable. Higher rates of spin lead to better stability, and for a given rate of spin, there is generally a range of velocities that are stable.

Even a slight deformation in a disc (called a "Taco," as extreme cases look like a taco shell) can cause adverse affects when throwing long range. It can be observed by holding the disc horizontally at eye level and looking at the rim while slowly rotating the disc.

See also

• Polish horseshoes

Further reading

• Stancil. E. D., and Johnson, M. D.; Frisbee, A Practitioner's Manual and Definitive Treatise, Workman Publishing Company, New York (July, 1975); ISBN 978-0-911104-53-0
• Norton, Gary; The Official Frisbee Handbook, Bantam Books, Toronto/New York/London (July, 1972); no ISBN
• Danna, Mark, and Poynter, Dan; Frisbee Players' Handbook, Parachuting Publications, Santa Barbara, California (1978); ISBN 0915516195
• Tips, Charles, and Roddick, Dan; Frisbee Sports & Games, Celestial Arts, Millbrae, California (March 1979); ISBN 978-0-89087-233-8
• Tips, Charles; Frisbee by the Masters, Celestial Arts, Millbrae, California (March 1977); ISBN 978-0-89087-142-3
• Morrison, Fred & Kennedy, Phil; Flat Flip Flies Straight, True Origins of the Frisbee, Wormhole Publishers, Wethersfield, CT (January 2006); ISBN 0-9774517-4-7
• Lorenz, Ralph; Spinning Flight: Dynamics of Frisbees, Boomerangs, Samaras and Skipping Stones, Copernicus, New York (September 2006); ISBN 978-0-387-30779-4

External links

• Frisbee Collective: gallery of over 200 Frisbee from all over the globe
• World Flying Disc Federation – international sports governing body for flying disc games
• Flying Disc Federation of Pakistan – National Federation for flying disc games in Pakistan
• Official Frisbee website by Wham-O, manufacturer of Frisbee brand flying discs
• Professional Disc Golf Association Governing body for professional disc golf