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Spin mass in a vacuum, efficiency?

  1. Mar 23, 2015 #1
    Hey guys I was wondering what would happen if:

    took a ball neo magnet, balanced it on a few other magnets to basically make it a frictionless bearing. Then spin the ball magnet to 10k rpm. But do all this in a box thats a vacuum.

    Would the neo ball magnet spin basically for a VERY long time since there is no or very little friction since it probably wouldn't be a 100% vacuum?

    What if you could make the box be 100% vacuum, would it spin forever?
  2. jcsd
  3. Mar 23, 2015 #2


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    Science Advisor

    Air isn't the only source of friction. Even with a levitated magnet, its magnetic field will be changing relative to the magnetic fields it is being supported by. That is cause a loss of energy- i.e. friction.
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