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Homework Help: Ratational Dynamics- PLEASE HELP

  1. Jan 9, 2008 #1
    1. The problem statement, all variables and given/known data
    A small 650 gram ball on the end of a thin light cord is rotated in a horizontal circle of radius 1.2 m. Calculate the torque needed to keep the ball rotating at a constant angular velocity if air resistance exerts a ofrce of 0.020 N. Ignore the rod's moment of intertia and air resistance.

    2. Relevant equations

    T= Ia(alpha)

    3. The attempt at a solution

    Well I found the moment of inertia but Im stuck on where to go next. Please help me!
  2. jcsd
  3. Jan 9, 2008 #2


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    Homework Helper

    calculate the torque due to the air resistance using your other equation for torque
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