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I have a query which I cannot resolve by finding enough arguments. A perfectly round wheel that also doesn't have any contractions due to gravity is placed in a perfect vacuum, so no drag is present. Will it stop due to friction force or will it roll forever?

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marked as duplicate by sammy gerbil, Martin, Community Mar 12 at 21:45

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    $\begingroup$ Rolling does not have to be hindered by gravity. In the idealized scenario of a uniform wheel rolling over a surface here on Earth, the wheel will also never stop rolling because gravity has no influence (causes no torque). $\endgroup$ – Steeven Mar 11 at 9:21
  • $\begingroup$ By gravity I didn't mean Earth. Besides putting in the gravitational field 20 stronger then ours may affect the rigidity of the wheel, so technically if no round structure can be formed in such a field there would be no place for rolling. $\endgroup$ – Anton Kovalyov May 4 at 20:12
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Any real-world wheel will eventually come to rest due to rolling resistance. All materials will have some slight deformation at the contact patch between the wheel and the surface it's rolling on. As long as there is contact between the two (i.e. the wheel is in fact rolling), there will be a force and deformation, and that is true regardless of gravity or air resistance. In a perfectly idealized scenario with a completely rigid wheel and rolling surface, the wheel would roll forever in the absence of air resistance, but the stipulation of a wheel with no rolling resistance doesn't seem to be part of your question.

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  • $\begingroup$ Thank you, I will google more about the rolling resistance/ $\endgroup$ – Anton Kovalyov Mar 12 at 21:52
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According to classical physics, the wheel can roll forever provided there is no friction and the motion of the wheel is perfectly symmetrical so that no energy can escape in the form of radiation. E.g. a quadrupole moment would cause gravitational radiation to be emitted which will slow down the wheel.

However, due to quantum mechanical effects, the wheel will slow down even under ideal conditions. A rotating wheel will exhibit rotational superradiance, it will emit electromagnetic radiation even in a perfect vacuum when no radiation is incident on the rotating wheel.

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  • $\begingroup$ Ahaha, thanks, but quantum mechanics part sounds a little hard for me. I will try to research it. $\endgroup$ – Anton Kovalyov Mar 12 at 21:52

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