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Code Number: 1Q60.35
Demo Title: Football
Condition: Good
Principle: Torque & Stable Axis
Area of Study: Mechanics
Equipment: Football.
Procedure:
When spun the frictional torques will cause the football to rotate about its statically unstable axis. In the case of the football, spin it about its short axis and it will eventually stand up on its point.
References:
- Kenneth Brecher and Rod Cross, "Physics of the PhiTOP®", TPT, Vol. 57, #2, Feb. 2019, p. 74.
- George Barnes, "Tippy Top Thoughts", TPT, Vol. 25, #4, April 1987, p. 200.
- Ralph Baierlein, Matthew Treptow and Mike Flynn, "Spinning Footballs and Class Rings", TPT, Vol. 24, #6, Sept. 1986, p. 361.
- D. Rae Carpenter, Jr., "L'Eggs Demonstrations", TPT, Vol. 15, #3, Mar. 1977, p. 188.
- George D. Freier, "The Tippy-Top", TPT, Vol. 5, #1, Jan. 1967, p. 36.
- Peter J. Brancazio, "Rigid-Body Dynamics of a Football", AJP, Vol. 55, #4, Apr. 1987, p. 415.
- James C. Lauffenburger, "A Large-Scale Demonstration of the Tippe-Top", AJP, Vol. 40, #9, Sept. 1972, p. 1338.
- Mu-18, Freier and Anderson, A Demonstration Handbook for Physics.
- M-788, "Stability of Spinning Objects", DICK and RAE Physics Demo Notebook.
- Tik Liem, "The Spinning Football", Investigation to Science Inquiry, p. 390.
- The PhiTOP Instructions, Explained.