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Homework Help: Finding rotational inertia of a yo-yo

  1. Nov 3, 2006 #1
    A yo-yo shaped device mounted on a horizontal frictionless axis is used to lift a 30kg as shown. The outer radius R of the device is 0.50m, and the radius r of the hub is 0.20 m. Wen a constant horizontal force F of magnitude 140N is applied to a rope wrapped around the outside of the device, the box, which is suspended from arope wrapped around the hub, has an upward acceleration of magnitude 0.80 m/s^2. What is the rotational inertia of the device about its axis of rotation?

    http://img438.imageshack.us/img438/7076/problemci9.jpg [Broken]
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Nov 3, 2006 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Well... where's your work? :grumpy:

    Hint: Apply Newton's 2nd law to both the yo-yo and the box. Take advantage of the information given and you'll be able to solve for the rotational inertia.
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