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Sounds of Moving Objects

  1. Aug 27, 2008 #1
    Hi, I was wondering what branches of physics and mathematics deals with calculating the type of sound produced when various shaped objects move in the air at relatively slow speeds. Specifically I was wondering if it would be possible to move an object, say to spin a pin wheel, by using a very sensitive microphone to pick up the sound it makes whilst moving and then applying that sound at that location with a speaker. Plus, does anyone know where I can find out more about the fact that a light piece of cardboard will be attracted to a vibrating tuning fork.

    Thanks,
    Ultros
     
  2. jcsd
  3. Aug 27, 2008 #2

    FredGarvin

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    Science Advisor

    Aeroacoustics is your best bet.

    It sounds like you are trying to form some kind of perpetual motion machine by using the sound through an amplifier to further propel the device. Is this so?
     
  4. Aug 27, 2008 #3

    russ_watters

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    Staff: Mentor

    Please note: perpetual motion is crackpottery and we don't allow crackpottery here.

    Please note also: amplifiers require external power to drive speakers.
     
  5. Aug 27, 2008 #4
    Garvin,
    Thanks for pointing me to aeroacoustics. I wasn't really thinking about perpetual motion just wondering if I could use sound to control the motion of a pinwheel. It looks like I'll have to be pretty far along in a mechanical engineering degree to figure everything out.

    Waters,
    Show me why you think the universe isn't perpetual motion.
     
  6. Aug 27, 2008 #5

    DaveC426913

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    Gold Member

    Well, because it will run down and stop.
     
  7. Aug 27, 2008 #6

    russ_watters

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    Staff: Mentor

    Besides what was already said, you need to understand what is actually meant when someone says "perpetual motion". There are three types of perpetual motion machines, one for each of the laws of thermodynamics they violate:

    http://en.wikipedia.org/wiki/Perpetual_motion#Classification
     
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