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Homework Help: Speed of a point on the rim?

  1. Dec 9, 2008 #1
    1. The problem statement, all variables and given/known data

    A thin, 100.0 g disk with a diameter of 8.00 cm rotates about an axis through its center with 0.150 J of kinetic energy.

    What is the speed of a point on the rim?


    3. The attempt at a solution

    1/2mv^2 = 0.15
    v = 1.73m/s

    I know
    Vt = angular velocity x r

    I am not sure how to solve foe the angular velocity
     
  2. jcsd
  3. Dec 9, 2008 #2
    1/2 mv^2 = kinetic energy, correct. However, here you're dealing with rotational KE. You need a different formula. Does that help?
     
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