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Thread: speed of sound

  1. #1 speed of sound 
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    Hallo all,

    what is the speed of sound in gases?

    I know that the speed of sound is: the square root of the buldmodulus divided by the density, but what with the following definition then: v= frequence x lambda.

    Or are they both the same? Just 2 ways of calculating the speed of sound?


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  3. #2 Re: speed of sound 
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    Quote Originally Posted by josse
    Hallo all,

    what is the speed of sound in gases?

    I know that the speed of sound is: the square root of the buldmodulus divided by the density, but what with the following definition then: v= frequence x lambda.

    Or are they both the same? Just 2 ways of calculating the speed of sound?
    No they are not the same. v= frequence x lambda is a general statement about waves. It tells you nothing specifically about sound.


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  4. #3  
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    ok,

    so the speed of the wave is not the same as the speed of the sound?

    you have to look at them completely different then?


    ok and what about the next problems then:

    Imagine I have a soundwave in a pipe, when I would put this pipe in the water, would the wavelength of that soundwave change then or not?
    I think it would change, because the medium were the soundwave has to travel trough changes.
    But I am not sure if this is accurate.

    and another question:

    If you change the frequence of a soundwave (make it higher) would the speed of the wave change then?
    I think not, because you stay in the same medium.
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  5. #4  
    Forum Professor leohopkins's Avatar
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    Quote Originally Posted by josse
    ok,

    so the speed of the wave is not the same as the speed of the sound?

    you have to look at them completely different then?


    ok and what about the next problems then:

    Imagine I have a soundwave in a pipe, when I would put this pipe in the water, would the wavelength of that soundwave change then or not?
    I think it would change, because the medium were the soundwave has to travel trough changes.
    But I am not sure if this is accurate.

    and another question:

    If you change the frequence of a soundwave (make it higher) would the speed of the wave change then?
    I think not, because you stay in the same medium.
    Well, due to the doppler affect, the soundwave would constantly be getting longer and longer in length, so, yes the frequency is affected this way; however. The frequency to my knowledge will be unaffected the by the media.
    The hand of time rested on the half-hour mark, and all along that old front line of the English there came a whistling and a crying. The men of the first wave climbed up the parapets, in tumult, darkness, and the presence of death, and having done with all pleasant things, advanced across No Man's Land to begin the Battle of the Somme. - Poet John Masefield.

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  6. #5  
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    Well, due to the doppler affect, the soundwave would constantly be getting longer and longer in length, so, yes the frequency is affected this way; however. The frequency to my knowledge will be unaffected the by the media.
    is this an answer to my second question?

    and I do not see where the doppler effect comes in order with these problems.

    keep in mind that I do not mean that I move the object, I simple do the test 2 times:
    1 time with the pipe in air, second time in water (for the first question).

    And for the second questions, the source and and listner do not change position.
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