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I believe that if you push an object, say a metal pole, the disturbance travels through the object at the speed of sound in that material. In that case, what happens if you continuously push one end of the pole at the speed of sound? Does the pole keep getting compressed, since the disturbance would be traveling at the same speed as the end of the pole being pushed?

EDIT: I'm adding an image to hopefully better explain the question. enter image description here In the image, we have a metal pole of length L at time t = 0. Let's say that the speed of sound through the pole is v. Now, at t = 0 we start pushing the pole at one end with speed v. At time t = L/2v, we've pushed one end of the pole by a distance L/2. But, since the disturbance is also moving through the pole with speed v, the disturbance has not reached the other end of the pole yet. So, that would mean that the other end of the pole has not moved yet. Does that mean that the pole now has a length L/2?

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  • $\begingroup$ Question is kind of misnomer to those who recently heard the word '' relativity''. $\endgroup$
    – Jack Rod
    Jun 13 '20 at 6:18
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Speed of sound is nothing but the speed at which vibration propagate, speed of sound depends upon the medium and that's it, it is not dependent on the speed of source which produce the vibration so speed f the sound remains same. And the speed (or velocity) of a wave in a medium can be measured by noting the position of a particular feature of the wave as a function of time. You can measure a speed in this way whether you are at rest relative the medium or not. But (with the sole exception of light) the speed set by the wave mechanism is the speed measured by on observer at rest relative the medium. Walk along the shore by a pond and throw in a pebble: the wave moving in the direction of your walking will move more slowly relative you than the ones going backward.

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