rotating rod

[mysterious_man]

Hi All:
Imagine there is a rod that can rotate around and axis penetrating one of its ends and perpendicular to the rod, say we are rotating this rod by angular velocity omega, so what prevent the far end of the rod from exceeding the light speed if we just increase omega (I don't think that omega has limit) and you know that the normal radius of the circle (the rod) length is normal to motion direction, so it seems there will be no length contraction! and speed is V=omega*R
Where R is the length of the rod.
By the way. if you integrated the relativistic mass of relativistic  even moment of inertia you will be surprised it is not infinite if the far end has C speed!!!
Could you please explain?
Ahmed

[curiosityandthecat]

Could you please explain?

...nope!  

[PipeBox]

OK, relativity gets weird, I'll try to keep it simple.  There is no object that could withstand circular motion at the speed of light.   It would break because no object possesses infinite rigidity and the parts of the rod approaching the speed of light would have far more mass than the anchored end.  Assuming it could be kept intact, it would have to bend in an epic fashion that would keep the end of the rod below the speed of light.  Motion can only be transferred through an object at the speed of sound in that object.  As such, the speed varies.  It's higher in silver than it is in water than it is in air.  Anyway, assuming the object didn't break, as you approached the speed of light parts of the object would begin moving ahead faster than the material could transfer the motion.  You'd have to move the "stationary" end faster than light to break this effect.  Which again, becomes impossible.  The only way to get around this is if you either already have an object moving entirely at the speed of light, where no acceleration (and no acceleration delay) is involved, or if you had an object where the motion transferred faster than the speed of light (something that dense would collapse itself).

Be warned, I'm no physicist, but if this doesn't make any sense to anyone, I'll try to clear it up.  I may even do further research.  If I'm dead wrong about any of this, and you know what is wrong with the OP's proposal, teach me.  I love this stuff.  

[Jolly Sapper]

Wow.. i feel smarter already.

[Asmodean]

Isn't the speed of light unachievable because (in simple terms) the energy requirement to accelerate to the speed of light would be infinite? (or practically exceeding the capacity of the object being accelerated)

[PipeBox]

For a vehicle, yes, it fast becomes impossible to have enough fuel, but that only means vehicles are practically impossible so far as we can see.  But what about creating a stationary facility that could draw off the power of multiple stars or even entire galaxies?  Our technology is nowhere near this level, but assuming you had the means, then so long as the energy required to reach the speed of light doesn't go infinite or exceed the total energy of the universe (it comes nowhere near it for reasonably sized objects), you could feed it all into a local, non-moving propulsion system, like the one driving our thought-problem-rod.  Even with absurd amounts of energy, you can't bring the far end of the rod above the speed of light.  The physical limitations of the universe and the materials that exist within it come into play.

I need to go to bed now.  *face falls on keyboard*

[Asmodean]

)

[curiosityandthecat]

Heh heh.. heh.. he said rod.

[Tanker]

Corret me if im wrong on this, since the center would be traveling slower then the ends, the ends would be approacing near c velocity sooner then the center. As the ends aproched c velocities they would be affected by space time dialation a greater rate the farther from the center you got. Woulden't the rod then resemble a duel spiral form (at least to an outsid observer). The center might approach infinatly close to c velocities but wouldent the ends approach fractionaly closer, yet still not breaking the light barrier.

[Asmodean]

Corret me if im wrong on this, since the center would be traveling slower then the ends, the ends would be approacing near c velocity sooner then the center. As the ends aproched c velocities they would be affected by space time dialation a greater rate the farther from the center you got. Woulden't the rod then resemble a duel spiral form (at least to an outsid observer). The center might approach infinatly close to c velocities but wouldent the ends approach fractionaly closer, yet still not breaking the light barrier.

...That's sort of what I was saying. I think it's correct, but my physics has, as stated, layers of rust on it in this particular (and some other) area(s)  

[Tanker]

...That's sort of what I was saying. I think it's correct, but my physics has, as stated, layers of rust on it in this particular (and some other) area(s)

Sorry I didden't mean to step on your toes. I find it really easy to visualise the dynamics of phisics, but I really have trouble folowing the math. Looking at your chart yes you are right I pretty much the said the same thing you did. I guess I just had to follow my somewhat iregular thought path before I could undrstand the math better.

[Asmodean]

Sorry I didden't mean to step on your toes. I find it really easy to visualise the dynamics of phisics, but I really have trouble folowing the math. Looking at your chart yes you are right I pretty much the said the same thing you did. I guess I just had to follow my somewhat iregular thought path before I could undrstand the math better.

I seem to be the exact opposite of you though - math I can follow. It's the physics part of it that gets me. Have not done it for 6 years though, so no real wonder.