How does the speed of light affect the rotation of a disc?

  • Thread starter zarbanx
  • Start date
In summary, according to the theory of relativity, nothing can be infinitely rigid. If a rod is eight light minutes long and one end is moved, the movement will only be transmitted through the rod at the speed of sound in the material it is made of. This means that the other end of the rod will not start moving until after eight minutes, disproving the idea of an infinitely rigid object.
  • #36
When you ignore everything that needs to be ignored, the upshot is that:

as the rim approaches c, it gets harder and harder to spin the disc faster. It will take an infinite amount of energy to accelerate the disc till the rim is moving at c - just like it takes an infiinite amount of enrgy to accelerate a rocket to c.
 
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  • #37
DaveC426913 said:
When you ignore everything that needs to be ignored, the upshot is that:

as the rim approaches c, it gets harder and harder to spin the disc faster. It will take an infinite amount of energy to accelerate the disc till the rim is moving at c - just like it takes an infiinite amount of enrgy to accelerate a rocket to c.

Well, I guess that ends it.
 

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