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Homework Help: Angular speed of wrapper string

  1. Apr 3, 2008 #1
    1. The problem statement, all variables and given/known data

    A string is wrapped several times around the rim of a small hoop with radius 8.00 cm and mass 0.180 kg . The free end of the string is held in place and the hoop is released from rest (the figure ). After the hoop has descended 60.0 cm, calculate angular speed and speed at the center
    2. Relevant equations
    w= omega

    w = w+ at
    K = 1/2 I w^2 ?

    3. The attempt at a solution

    I'm really unsure how to approach this problem and don't exactly know where to start
  2. jcsd
  3. Apr 3, 2008 #2


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    Science Advisor
    Homework Helper

    Use energy conservation. Add linear KE=(1/2)*m*v^2 and gravitational potential energy PE=mgh to your list of equations.
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