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Homework Help: Angular velocity and time

  1. Mar 22, 2008 #1
    1. The problem statement, all variables and given/known data
    A spool of thin wire rotates without friction about its axis. A man pulls down on the wire with force of 14.9N. How long does it take to increase the angular velocity of the spool from 11.0rad/s to 35.0rad/s?
    Icm = 0.490kg*m^2
    Inner radius, r = 0.280m
    Outer radius, R = 0.600m

    2. Relevant equations

    3. The attempt at a solution

    im not sure how to do this. i know the equation for angular velocity but i dont know what to do with the force and time
  2. jcsd
  3. Mar 22, 2008 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Figure out the angular acceleration using Newton's 2nd law for rotation.
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