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When is the wave propagating in a solid transverse and when is it longitudinal? Because I've been taught that both kinds can propagate in a solid
- Annie (age 18)
You were taught correctly. (Followers of this site know that we rarely say that.) As for what type of wave is propagating in a particular case, that just depends on how the wave was generated.
Say that you hit a big steel block on top with a hammer. Just picturing how the atoms are displaced by the blow, you can see that there should be a compressional (longitudinal) wave going downward. Out to the sides, there should be transverse waves.
Life is even more complicated than that in the field of seismology. Not only do transverse and longitudinal waves exist, called respectively s-waves (secondary) and p-waves (primary), but there are several others which deal with surface phenomena. See http://en.wikipedia.org/wiki/Seismic_wave for some interesting and gory details.
(published on 03/30/2011)
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