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Homework Help: Speed and its centripetal force of circling object

  1. Jun 18, 2005 #1
    an object mass of .5kb revovles uniformly in cirlce horizontal frictionless surface. it is attached by .75 m cord to pin set in surface. if object makes 2 complete revolujtions per second, find its speed and its centripetal force

    mg = m(v2/r)
    gr = v2
    v = sq root of gr
    v = sq root of 9.8*.75
    v = 2.7 m/s2

    anyone wanna do me a favor, and check if i'm doing' this right,
    thanks a lot..
  2. jcsd
  3. Jun 18, 2005 #2

    Andrew Mason

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    Science Advisor
    Homework Helper

    Gravity has nothing to do with this problem. The centripetal force is mv^2/r. All you have to do is work out what v is from:

    [tex]v = 2\pi r/T[/tex] where T = .5 sec.

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