1K20.70 - Falling Bottle Capstan
Hang the apparatus over a horizontal rod in an Atwood's arrangement and show that the sand filled bottle is much heavier than the stopper. Then pull the sand filled bottle close to the rod by pulling on the stopper. Lift the stopper to an angle of 15 to 20 degrees above the horizontal rod. When you let go of the stopper, the bottle will fall about 1/2 to 2/3's the length of the string before it is stopped by the wrapping action of the stopper around the horizontal rod.
- Ralph McGrew, "A Simple Mechanical Experiment on Exponential Growth", TPT, Vol. 53, # 4, April 2015, p. 222.
- Michael Vollmer, Klaus-Peter Mollmann, "Ring Falling into a Chain: No Magic - Just Physics", TPT, Vol. 49, # 6, Sept. 2011, p. 335.
- Wen-Tang Lee, Huang-Wen Hsiao, "Tension of a Soft Spring in Contact with a Cylinder", TPT, Vol. 47, # 9, December 2009, p. 596.
- Martin Gardner, "The Falling Keys", TPT, Vol. 28, # 6, Sept. 1990, p. 390.
- James R. Klein, "Wrapping Around a Pole", TPT, Vol. 16, # 9, Dec. 1978, p. 640.
- Paul G Hewitt, "Not a Wrap- Around", TPT, Vol. 17, # 4, Apr. 1979, p. 224.
- R. E. J. Sears, "Comment on 'A Surprising Mechanics Demonstration,' By A. R. Marlow", AJP, Vol. 63, # 9, Sep. 1995, p. 854.
- David J. Griffiths, Tyler A. Abbott, "Comment on 'A Surprising Mechanics Demonstration,' by A. R. Marlow", AJP, Vol. 60, # 10, Oct. 1992, p. 951.
- A. R. Marlow, "A Surprising Mechanics Demonstration", AJP, Vol. 59, # 10, Oct. 1991, p. 951.
- Eugene Levin, "Friction Experiments with a Capstan", AJP, Vol. 59, #1, Jan. 1991, p. 80.
- Clifford Bettis, "Capstan Experiment", AJP, Vol. 49, #11, Nov. 1981, p. 1080.
- Martin Gardner, "The Falling Keys", Science Tricks, p. 34.
- Jearl Walker, "1.178, Hanging Goblet, Ready to Crash", The Flying Circus of Physics Ed. 2, p. 78.
- Robert Ehrlich, "The Matchbook and the Keys", Why Toast Lands Jelly-Side Down, p. 74.
Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist. The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose. The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources. Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks. These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage. Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.