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Homework Help: Need help- Force of friction in a circle.

  1. Nov 3, 2009 #1
    1. The problem statement, all variables and given/known data
    A 45-kg merry-go-round worker stands on the ride's platform 6.3m from the center. If her speed as she goes around the circle is 4.1 m/s, what is the force of friction necessary to keep her from falling off the platform?

    2. Relevant equations
    mu=v^2/rg (derived from [mu]g=v^2/r

    3. The attempt at a solution
    I don't believe the 6.3m is relevent to the problem.

    I believe Fnet=sigmaFx=theta=m*a

    I am not really sure how to attack this problem and some help would be very nice.
  2. jcsd
  3. Nov 3, 2009 #2


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    Gold Member

    You got the right equation:

    [tex]\mu = \frac{v^2}{rg}[/tex]

    now tell me... what does the r mean in:

    [tex] A_c = \frac{v^2}{r}[/tex]
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