If I had a 1000km long steel rod and I pushed one end of it, when would someone standing at the other end observe movement? Would it travel exactly the speed of sound in that material, or is the speed of sound variable depending on the amplitude of the impulse (ie would it travel quicker)?
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1$\begingroup$ As an example of an experiment to find, Speed of sound in solid. $\endgroup$– FarcherCommented Dec 5, 2021 at 8:06
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3 Answers
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In the case of steel the atoms are well organized in a lattice, facilitating a directional chain-reaction of movement through the rood all the way to the end.
The individual atom works like a little pendulum (harmonic oscillator). An you might know that the frequency of a pendulum or a swing does not depend on the amplitude. Hence the use of pendulums in clocks.
So, within a reasonable range of initial impact the properties of the material and not the amplitude will decide the propagation velocity
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To clarify the preceding answers:
The maximum possible speed of any mechanical impulse in a solid bar is the speed of sound in the material from which the bar was made. This is roughly 10,000 feet per second in steel.
answered Dec 5, 2021 at 19:16
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The speed of sound in a solid doesn't depend on the magnitude of the impulse.
The pressure ($P$) waves travel fastest and are unaffected by the size of the impulse. Shear waves ($S$) waves might also be created in a large body, depending on the nature of the impulse, they travel more slowly than the $P$ waves.
answered Dec 5, 2021 at 10:00