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Rotational Center of Mass question

  1. Jun 3, 2006 #1
    On earth, under the influence of gravity, when an object is spun/rotated and then released, it will find its center of mass and rotate around that as it falls. So, if you spun a very straight uniform stick at its exact center of mass say 1 meter off the ground and then released it, it will drop straight down: continuing to spin at its center of mass as it falls. However, if you spun it off center and released it, it will always find its center of mass but will not drop straight down, instead it will fall to the left or right (depending on which way you are spinning it). Hopefully that wasn't explained too confusingly.....

    Anyway here’s the question. In an environment without gravity, will a rotating object that’s spun off center naturally find its center of mass when released? Or will it just sit still and spin lopsided - if you catch my meaning. I seem to think it will always find its center of mass when rotating whether in the presence of gravity or not. Anyone know the answer to this? Thanks!

    Note that when I'm saying spin, or spun, I'm referring to rotation. I'm also restricting the rotation to just 1 axis - although I think the same answer will apply to multiple axes of rotation.
  2. jcsd
  3. Jun 3, 2006 #2


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    Your intuition is correct. The object will fly off in the direction its CoM was moving when it was released, and rotate around its CoM.
  4. Jun 3, 2006 #3
    Excellent! Thank you very much for you help.
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