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Why do things spin?

  1. May 2, 2010 #1
    Solar systems, planets, spiral galaxies. (Atoms?) What causes objects to spin, rather than just wobble around?
    Last edited: May 2, 2010
  2. jcsd
  3. May 2, 2010 #2


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    Staff: Mentor

    Welcome to PF.

    What does "wobble around" mean? If something has a force applied offcenter, it spins because of the uncentered force. I'm not sure quite how else to explain it.
  4. May 2, 2010 #3


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    Science Advisor

    I share russ's confusion with the term "wobble" but I think the answer to this analogous question might help:

    Why do things move in a straight line rather than just curve around?

    Of course, the answer to this is that any curving motion requires a force to be acting. The situation is the same for rotational motion.
  5. May 3, 2010 #4
    Conservation of angular momentum.
  6. May 3, 2010 #5

    Thank you, that makes perfect sense.
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