I have a seemingly trivial question to ask here. just imagine the followiing scenario.

There is a rod which is 3X10^8 m long, if the rod has a ball attached to one end and is pivoted at the other, and the rod is given an angular velocity of 1 rad/s. then will the ball have an instantaneous linear velocity of v= r X angvel.=speed of light,
or is there a fundemental flaw in the scenario so envisaged?

What exactly is the point of this mind experiment?

That it would be possible to accelerate the ball at the end to the speed of light?

There is a fundamental flaw, you would never be able to accelerate/spin up the rod to the angular velocity of 1 for the very same reason why you wouldn't be able to accelerate the ball itself to speed of light. The mass of the ball increases as it's speed goes up. At the speed of light its mass would equal infinity and since the acceleration, regardless if it's angular or not, requires energy relative to mass, as mass grows with velocity, you would require inifinite amounts of energy as you get closer to speed c at the outside end of the spinning rod.

vx220 is correct.

In practical terms, the rod would bend and eventually break as it was sped up, long before the ball at the end reached the speed of light.

The mass of the ball increases as it's speed goes up.



would you mind expounding on this a bit please.

would you mind expounding on this a bit please.

what he is saying is that the material of which the rod is made of will not be able to withstand such shear force. not that I agree or not agree with it.

Would you mind expounding on this a bit please.

One way of looking at relativity is that objects gain mass as they get faster. When you push an object to accelerate it, part of that push goes into increasing the speed of the object, and part goes to increasing its mass. At low speeds, most of the push goes to increasing the speed, and the mass doesn't change much. But as the speed approaches the speed of light, essentially all of the push goes into increasing the mass and practically none goes to increasing the speed. That's one way of explaining why the speed of an object can't exceed the speed of light.

This is not an exact explanation, but it gives you a rough idea.

Look up relativistic mass on google.

You are very smart to have the question!
Relativists try to ignore the question.
Dr Klauber tried hard to publish his papers about it.
Relativists try to turn him down.
See his papers:

Klauber, R.D.: 1999, Am. J. Phys. 67, 158
Klauber, R.D.: 2006, http://arxiv.org/abs/gr-qc/0604118

My answer: no rotational frame of infinite scale!!!!
No force can hold up such frames.

We need to give up such frame in the same way we give up Newtonian inertial frames by accepting Special Relativity!

thank u for the information..i gues i have to fine tune my mathematical skills to fully comprehend what was suggested in that paper