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Homework Help: Centrifugal Force: Are these equal?

  1. Feb 16, 2008 #1
    Good Evening to all,

    I have been working on the following problem for the past several days and have finally come to the end of my rope. I hate to admit defeat but I do need some help. I'm almost certain I'm simply missing something thats embarassingly simple....

    This is the problem exactly as it appears on the page:

    2. Centrifugal force is given by the following equation:

    F = m [tex]\omega[/tex]^2 r

    Where F = Centrifugal force
    m = mass
    [tex]\omega[/tex] = angular velocity
    r = length of radius

    A student told me the other day that centrifugal force on a mass m kg, rotating at an angular velocity of [tex]\omega[/tex] rpm and at a radius of r feet, is given by the following equation:

    F = 3.342 x 10^-3 m [tex]\omega[/tex]^2 r [Newtons]

    Are both equations correct? Explain?

    I know that this means I need to take the F equation, break it down into its base SI units and build it back up taking the meters to feet and seconds to minutes conversion into consideration.
    I know that the conversion for meters to feet is 3.28084. What am I missing?
    Last edited: Feb 16, 2008
  2. jcsd
  3. Feb 16, 2008 #2
    Sorry I'd thought I'd manage to find where I was going wrong but apparently not ...
    Last edited: Feb 16, 2008
  4. Feb 16, 2008 #3
    F = kg x .10472^2(rad/sec) x .3048(r)
    F = 3.34252x10^-3 m w^2 r

    It was my conversion directions that was causing all the problems.
    Last edited: Feb 16, 2008
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