1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook