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Rotation vs. Translation

  1. Dec 16, 2009 #1
    http://cheeseparade.com/diagram.png [Broken]

    Imagine a sphere on a frictionless surface. A string is attached to the top of the sphere, as shown. If a force is applied to the string, how will the sphere move? Will there be any torque at all, even though there is no friction? Or will the sphere move in exactly the same way as if the string was attached to the side of the sphere?
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Dec 16, 2009 #2

    A.T.

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    Sure. Your scenario is equivalent to a sphere floating in space. If the force doesn't go through the center of mass, it will start rotating.
     
  4. Dec 16, 2009 #3
    Ok, thats what i figured. But will there be translational movement as well? If so, how can you describe the force that acts on the center of mass as a function of the force that acts at the top of the sphere?
     
  5. Dec 16, 2009 #4

    A.T.

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    Yes
    They are the same
     
  6. Dec 16, 2009 #5
    Ok, thanks for you help!
     
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