Spin mass in a vacuum, efficiency?

[supak111]

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 that's 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?

 

[HallsofIvy]

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.