Hypothetically, let's say I had a bar/stick made of a nonelastic material, which was long 300 000 km. Let's also say I was holding it at the end (well not me, some machine able to do that :) ) and pointing it in any direction (well, me, 'the machine' and the stick are somewhere in deep space).
IF I WERE TO PULL THE END I'M HOLDING TOWARDS ME, WILL THE OTHER END MOVE IN THE SAME MOMENT TOO !?
If yes, than there is some sort of energy that travelled faster than light.
If no, than that means the material was at one in time point longer than the original, which can't be, becose of the assumption it was a non elastic material. So if no, why?
It's a 'problem' I've been thinking on for quite a long time now and would appreciate serious and if possible scientifically grounded answers.
Thanks four your time.
2007-02-27 23:53:01 · 5 answers · asked by tomes12 2 in Science & Mathematics ➔ Physics
This is a good question.
I also don't believe that the laser pointer covers the same answer as the principal point of the question has to do with the rigidity of the material you are pushing.
I believe the answer lies basically in the relativity of speed on the 4 axis of space-time.
If you remember space has four dimensions (up and down, left and right, forward and backward and Einstein included time). Einstein believes that, at rest, we all traveled through time at the speed of light. It is when we start moving in the other axis that we "bleed" speed out of time. In essence, when you pull the stick you accelerate it on a forward-backward axis, reducing its speed in time (thus decelerating the speed of time). So, to both it will seem instantaneous ( I pull it moves, and the watcher at the other end will see the stick move), but if the "puller" could somehow see the other end, it would seem to him that the other end did not move when he pulled.
2007-02-28 00:42:48 · answer #1 · answered by MSDC 4 · 0⤊ 0⤋
There is nothing at all wrong with your question, and it is indeed similar to thought experiments conducted by Einstein and others in formulating and working with relativity.
The answer is that the far end of the rod would not move at the same time as you moved your end. The fastest possible transmission time would be the speed of light, but in reality then end cannot move faster than the speed of a shock wave in the medium, and this is typically the speed of sound in the medium.
A trickier thought experiment is this. Imagine you have a barn 100 m long and you stand at the door. A 110 m long rod is fired at the door at such a speed that its length contraction in your frame is 10%. You watch the front of the rod go into the barn, and then as the end of the rod goes in you slam the door. Now, is there a 110 m long rod in your 100 m long barn? ANd if so what happens next?
2007-02-28 00:45:44 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Sorry. Your puzzle is flawed. Hypothetical constucts can be usefull, but you have to be careful that they have some basis in reality and that you can apply every day experiences to them.
In your case you imagine an immense rigid straight rod. This rod, would have to have mass. To move such an object would require massive amounts of energy. The tensile strength of the material would have to be beyond anything we know to keep from breaking under the strain. To give give more tensile strength by making the diameter of the rod bigger only adds more overall mass.
Let me take your question and rephrase it. You have a laser pointer ( a really strong one)and you have it turned on at rest relative to you. The you launch the laser pointer, on a rocket straight backward at 1000 m/s. Does this mean that the light from the laser pointer is now travelling less than 186,000 miles/sec relative to you?
The answer is no, the light from the laser pointer still travels at the speed of light, the frequency of the light will shift toward the red end of the spectrum but still at light speed.
2007-02-28 00:15:38 · answer #3 · answered by SteveA8 6 · 0⤊ 1⤋
The real problem is that you are mixing "reality" with "fiction" in a certain sense. There are no perfectly non-elastic materials. All are made up of atoms and their solid constitution is due to electric forces on the whole. The transmission of an electric impulse is done with the speed of light and so it woud take a second in your hypothetical problem for the other end to "feel" the pull. This electrical force is NOT instantaneous.
2007-02-28 00:03:22 · answer #4 · answered by physicist 4 · 0⤊ 1⤋
wow what a question!!!...ure smart
i think the other side wont respond to the pull immediately
2007-02-28 00:02:13 · answer #5 · answered by lilmissy 2 · 0⤊ 0⤋