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About Torque and Force

  1. Jul 26, 2010 #1
    After understanding about torque,

    I got one question about it.

    Why we cant use it as τ =Iα istead of F=mv^2/r ?

    since both are forces about circular motion
    Last edited: Jul 26, 2010
  2. jcsd
  3. Jul 26, 2010 #2

    Doc Al

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    Staff: Mentor

    They describe different aspects of circular motion.
    This describes the centripetal (radial) force acting on an object that is moving in a circle at some speed.
    This describes the torque necessary to give some object (with rotational inertia I) an angular acceleration.

    If something moves in a circle at constant speed, then the angular acceleration is zero--no torque is needed. But there will be a centripetal force on the object.
  4. Jul 26, 2010 #3
    thx ...
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