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Understanding air particle velocity as cross product freq x disp

  1. Apr 17, 2012 #1
    I'm reading a book on microphones and came across the following:

    and then it goes off talking about something else...

    I feel stupid for asking this, but I don't get how the above equation works? For one, I thought cross products could only be be involving vectors? Aren't all the terms above scalars? Should I treat it as a dot product?

    Any help in understanding the above, so I can see how the terms affect each other is greatly appreciated!
  2. jcsd
  3. Apr 17, 2012 #2


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    I don't think it is a cross product. It looks like the standard equation for velocity of a particle moving in simple harmonic motion.

    I don't know why the book used ##\times## as a multiplication sign here.
  4. Apr 17, 2012 #3
    Thanks, AlephZero! Typical of me getting thrown off by poor notation...
  5. Apr 17, 2012 #4
    AlephZero: Are you saying that that equation is pretty much: [itex] v = - A\omega \sin \omega t [/itex]? Does that mean I can consider the "maximum particle displacement" in the first equation, as the amplitude, A?
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