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Free falling spinning rectangle

  1. Aug 6, 2004 #1
    A rectangular piece of paper spins rapidly about its longitudinal axis as it falls
    through the air.It takes longer to reach the ground than other shapes of paper.Why is this given that it spends a lot of time edge on to the flow of air and so encounters less resistance from the air than a surface of constant horizontal orientation?
    And could I generate enough electricity from a free falling propeller to do something useful with - even if it's only going to turn on a light so I can read a book as I parachute from a plane at 2 in the morning.
  2. jcsd
  3. Aug 8, 2004 #2


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    Science Advisor

    I don't know what you meant about air resistence and stuff,
    but I figure that the spinning part depends on start conditions
    of the fall, air streams, and lack of symmetry.

    As for generating power from a falling propeller, of course
    it could be done. But remember the saying (in reveres though ;) ):
    what comes down must first go up. :biggrin:

    Live long and prosper.
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