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Circles?

fottry55i6
in Classical Physics

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If you are spinning a circle made of paper, we know that the area near the edge is moving faster than the area near the centre. Does that mean that with a large enough circle, you could make the edge go faster than light??

No.

 

A real material would fall apart, and for a fictional material that didn't, there would be length contraction of any moving segment, giving you a curved geometry such that the circumference would ever exceed c. IIRC this thought experiment led Einstein into the curved geometry of General Relativity.

Not to mention the energy required to get something like that up to speed. Since the amount of torque needed is related to the angular momentum, which is related to its moment of inertia, which involves mass/radius.

Going by what they have said i'm probably wrong, but I would have thought that a 'hyperthetical' material that didn't fall apart should, in a vacuum, be able to get to ANY speed, as there would be no friction;Therefore it would keep any kinetic energy that it aquired, and would not lose its speed. If you could keep supplying more and more energy, it should just keep getting faster. :eyebrow:

Edited by New Zealand
Grammar

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