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Long Bar and the Speed of Light

  1. Sep 28, 2008 #1
    I was asked this today, and I cannot picture an answer. Say you had a long bar in a vacuum, billions of miles long. If a force was applied lengthwise on one end, would the other end immediately respond? Would reference frames matter in this instance? I know information cannot travel faster than the speed of light, and I have a basic understanding of special relatively, but i cannot picture what would happen in this case...
     
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  3. Sep 28, 2008 #2

    Fredrik

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    There are lots of threads about this. Perhaps someone who participated in one of them can post a link.

    The other end will not respond immediately. You will just create a mechanical wave that propagates at the speed of sound. (A longitudinal mechanical wave is, by definition, sound). If you hit it with a hammer that's moving faster than the speed of sound in that material, then you'll just break it and create a wave the propagates at the speed of sound.
     
  4. Sep 29, 2008 #3

    George Jones

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