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Homework Help: Uniform Circular Motion.

  1. Jan 24, 2010 #1
    1. The problem statement, all variables and given/known data

    What angular speed (in revolutions per
    minute) is needed for a centrifuge to produce
    an acceleration of 675 times the gravitational
    acceleration 9.8 m/s2 at a radius of 15.4 cm?
    Answer in units of rev/min.

    2. Relevant equations
    ac=4 pi2 r f2

    3. The attempt at a solution
    ok so first I found the acceleration which is 110.25 m/m2 and I converted the radius to meters r= .154 m then I solved for the frequency = ((110.25)/(4pi2.154))1/2 = 1979.137 rpm
    and my answer was wrong. Can you please tell me what error I made. thank you
     
  2. jcsd
  3. Jan 24, 2010 #2
    9.81 m/s^2 * 675 does not equal 110.25 m/m2
     
  4. Jan 24, 2010 #3
    Yeah, I fixed the acceleration and I got 3906900m/m2 and blugged it in again, and my answer was still wrong.
     
  5. Jan 24, 2010 #4
    umm acceleration is m/s/s not m/m/m
     
  6. Jan 24, 2010 #5
    I had to convert it, because they're asking for the angular speed in rev/minute
     
  7. Jan 24, 2010 #6
    what kind of physics are you taking?
     
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