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Wind Resistance Question

  1. Apr 20, 2005 #1
    Okay, so here's the thing...


    I need to find the Force pushing against a sign that is attached to a vehicle.

    The area (A) of the sign is 60"X28" which is 42.672 [tex]m^2[/tex]

    The velocity (v) that the vehicle will be moving is roughly 80 miles per hour which converts to 35.7632 [tex]\frac{m}{s}[/tex]

    The next 2 I'm not sure about....

    Air density (r) is 1.229 [tex]\frac{Kg}{m^3}[/tex]?
    [tex]C_D[/tex] (Coefficeitn of friction) of this sign (which the broad side will be hitting the wind head on) is 1.28?

    So I did all this calculation and got

    42929 N which is 9651 lbs. That is a hell of a lot of force. I was wondering if I did all this correct...please let me know. Thanks
  2. jcsd
  3. Apr 20, 2005 #2


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    Science Advisor

    There's your error.
  4. Apr 23, 2005 #3
    I would expect it to be in the 150 to 200 lb range.
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