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Nerd-gasm Question

Wiseone

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Suppose you have a rod, which is inflexible and so does not bend under any force or pressure. This rod is attached to a machine inside of a frictionless vacuum, this machine is attached to a power source of unlimited power and will spin the rod in a circular motion.

Now the far point of this rod will end up spinning faster than a point closer to its base because those two points must remain on the same degree in our 360 degree circle defined by all the points in space the tip of the rod will occupy as it spins. However the far end will be going faster because it has a great distance to travel than a point closer to its base and cannot bend.

Therefore by spinning the rod we can force the far end to exceed the speed of light by simply accelerating the base to a sub light speed? In fact if our rod was long enough the end could be accelerated to above light speed by the tiniest amount of force on its base.

Correct? No its actually impossible, even in a frictionless vacuum environment. But why not? Anyone who answers correctly gets a bingo button.
 

spud_meister

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If I remember correctly, the rod will contract and eventually turn into light, or explode due to reaching critical mass, can't remember which.
 

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Tashah is the expert on this but I guess since mass is increasing to infinity while the end point is reaching light speed, the force that is needed to spin the rod is increasing to infinity too.

mT = γm0

and

 
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tacomancer

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This is assuming that the tensile strength of the rod is such that it wont pull itself apart?
 

Winston Smith

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Suppose you have a rod, which is inflexible and so does not bend under any force or pressure. This rod is attached to a machine inside of a frictionless vacuum, this machine is attached to a power source of unlimited power and will spin the rod in a circular motion.

Now the far point of this rod will end up spinning faster than a point closer to its base because those two points must remain on the same degree in our 360 degree circle defined by all the points in space the tip of the rod will occupy as it spins. However the far end will be going faster because it has a great distance to travel than a point closer to its base and cannot bend.

Therefore by spinning the rod we can force the far end to exceed the speed of light by simply accelerating the base to a sub light speed? In fact if our rod was long enough the end could be accelerated to above light speed by the tiniest amount of force on its base.

Correct? No its actually impossible, even in a frictionless vacuum environment. But why not? Anyone who answers correctly gets a bingo button.
Because the transfer of energy from the center of the machine to the end of the rod can only take place at the speed of light, the shape of the rod will be increasingly distorted so that it will never reach light speed. And what youknowwho said.
 
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Andalublue

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Suppose you have a rod, which is inflexible and so does not bend under any force or pressure. This rod is attached to a machine inside of a frictionless vacuum, this machine is attached to a power source of unlimited power and will spin the rod in a circular motion.

Now the far point of this rod will end up spinning faster than a point closer to its base because those two points must remain on the same degree in our 360 degree circle defined by all the points in space the tip of the rod will occupy as it spins. However the far end will be going faster because it has a great distance to travel than a point closer to its base and cannot bend.

Therefore by spinning the rod we can force the far end to exceed the speed of light by simply accelerating the base to a sub light speed? In fact if our rod was long enough the end could be accelerated to above light speed by the tiniest amount of force on its base.

Correct? No its actually impossible, even in a frictionless vacuum environment. But why not? Anyone who answers correctly gets a bingo button.
Because Glenn Beck will mobilise a million people to protest and prevent unnatural physical behaviour?

Dunno. I failed Physics O-level.
 

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The Giant Noodle

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Suppose you have a rod, which is inflexible and so does not bend under any force or pressure. This rod is attached to a machine inside of a frictionless vacuum, this machine is attached to a power source of unlimited power and will spin the rod in a circular motion.

Now the far point of this rod will end up spinning faster than a point closer to its base because those two points must remain on the same degree in our 360 degree circle defined by all the points in space the tip of the rod will occupy as it spins. However the far end will be going faster because it has a great distance to travel than a point closer to its base and cannot bend.

Therefore by spinning the rod we can force the far end to exceed the speed of light by simply accelerating the base to a sub light speed? In fact if our rod was long enough the end could be accelerated to above light speed by the tiniest amount of force on its base.

Correct? No its actually impossible, even in a frictionless vacuum environment. But why not? Anyone who answers correctly gets a bingo button.
Because the particles that make up the rod can not exceed the light limit without turning into pure engery. Plus what about the parts in the machine? there is no such thing as frictionless!!! If you have UNLIMITED energy being put in to the machine... the engery MUST go somewhere.
 
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molten_dragon

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Suppose you have a rod, which is inflexible and so does not bend under any force or pressure. This rod is attached to a machine inside of a frictionless vacuum, this machine is attached to a power source of unlimited power and will spin the rod in a circular motion.

Now the far point of this rod will end up spinning faster than a point closer to its base because those two points must remain on the same degree in our 360 degree circle defined by all the points in space the tip of the rod will occupy as it spins. However the far end will be going faster because it has a great distance to travel than a point closer to its base and cannot bend.

Therefore by spinning the rod we can force the far end to exceed the speed of light by simply accelerating the base to a sub light speed? In fact if our rod was long enough the end could be accelerated to above light speed by the tiniest amount of force on its base.

Correct? No its actually impossible, even in a frictionless vacuum environment. But why not? Anyone who answers correctly gets a bingo button.
By e=mC^2, as you accelerate the rod, it gains mass. As it gains mass, the amount of energy required to further accelerate it grows. To accelerate the rod (or any part of it) to the speed of light would require an infinite amount of energy.
 

The Giant Noodle

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By e=mC^2, as you accelerate the rod, it gains mass. As it gains mass, the amount of energy required to further accelerate it grows. To accelerate the rod (or any part of it) to the speed of light would require an infinite amount of energy.
Thats what i said... but I said it better :cool:
 

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I think its like the Bills winning a superbowl. You can get close but never quite get there.
 

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Spare the rod already, wouldja? TIA!

Regards from Rosie
 

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By e=mC^2, as you accelerate the rod, it gains mass. As it gains mass, the amount of energy required to further accelerate it grows. To accelerate the rod (or any part of it) to the speed of light would require an infinite amount of energy.
But you have ulimited energy, and the rod cannot bend so it's far end cannot drag behind its near end.
 

Korimyr the Rat

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My primitive caveman brain is offended by the fact that this question exists.
 

tacomancer

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My primitive caveman brain is offended by the fact that this question exists.
If you are driving in a car at the speed of light and turn your headlights on, do they shine?

:2razz:
 

Wiseone

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I have a confession that I don't actually know the answer to this question. I think I was told that the rod, given unlimited power and and unbend-able rod, that the rod actually gets shorter to a point where its end would no longer be forced past light speed.

So hell if I know.
 

Aunt Spiker

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Suppose you have a rod, which is inflexible and so does not bend under any force or pressure. This rod is attached to a machine inside of a frictionless vacuum, this machine is attached to a power source of unlimited power and will spin the rod in a circular motion.

Now the far point of this rod will end up spinning faster than a point closer to its base because those two points must remain on the same degree in our 360 degree circle defined by all the points in space the tip of the rod will occupy as it spins. However the far end will be going faster because it has a great distance to travel than a point closer to its base and cannot bend.

Therefore by spinning the rod we can force the far end to exceed the speed of light by simply accelerating the base to a sub light speed? In fact if our rod was long enough the end could be accelerated to above light speed by the tiniest amount of force on its base.

Correct? No its actually impossible, even in a frictionless vacuum environment. But why not? Anyone who answers correctly gets a bingo button.
Yep. . . aside from going into "what would physically happen to said rod"

Now why didn't Einstein think of that when he said E-MC*2* ??
 

molten_dragon

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But you have ulimited energy, and the rod cannot bend so it's far end cannot drag behind its near end.
If you truly had an infinite amount of energy, you could accelerate the end of the rod to the speed of light (which is impossible of course, since there's no such thing as an infinite amount of energy), but not over it.
 

molten_dragon

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If you are driving in a car at the speed of light and turn your headlights on, do they shine?

:2razz:
Yes, they would. And the weird part is that as the person driving the car, you would still see the beams of light moving away from you at the speed of light.
 

Dav

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I'm sure there's a joke about rods in there somewhere.
Up to this point, I was reading the whole thread as a rod-related joke, assuming it to be intentional... shows how my mind works I guess.
 
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