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Accelerating object air resistance

  1. Jan 31, 2010 #1
    Ok so i have the distance travelled of an object assuming air ressistance is 0 and the distance travelled with air resistance included as well as the acceleration of the object, how would i calculate the coefficient of air resistance?


    Thanks
     
  2. jcsd
  3. Jan 31, 2010 #2
    If it's a simple shape you can find it on the internet, such as this chart:

    200px-14ilf1l.svg.png

    But if it's something more complex...which is pretty much anything, I don't think you can figure it out using paper and a pencil. Either through experiment, or maybe with some powerful physics program.
     
  4. Jan 31, 2010 #3

    ideasrule

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    Do you also know the initial launch angle or launch speed? If so, you can write a simulation program that predicts the projectile's range for different coefficients of air resistance, then see which one is the closest.
     
  5. Feb 1, 2010 #4
    There are two classifications of air drag; Stokes Law drag or turbulent drag, depending on whether the Reynolds number Re is below or above about Re ~1000. See

    http://en.wikipedia.org/wiki/Drag_(physics [Broken])

    The air drag for projectiles is usually turbulent, and the power loss (energy loss rate) is proportional to velocity cubed (see above url).

    Bob S
     
    Last edited by a moderator: May 4, 2017
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