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Retraction/reflection help please

  1. Jul 4, 2007 #1
    1. The problem statement, all variables and given/known data
    two vibrating sources emit waves in the same elastic medium. the first source has a frequency of 25 hz, while the frequency of the second source is 75hz. waves from the first source have a wavelength of 6.9 m. they reflect from a barrier back into the original medium, with an angle of relfection of 25 degrees. waves from the second source refreact into a different medium with an angle of incidence of 35 degrees. the speed of the refracted waves is observed to be 96 m/s.

    ok so i need help with the set up and the digram at this problem. i only learned reflection as an indivudual question and retraction as an individual question.


    my attemp was to draw the t lines, have one bouncing off from one and on the other flip side have only one bounc off..can anyone help and explain how to do this? greatly appreciated..im in grade 11 phyics corrospondants during the summer...and i need someone to help...
     
  2. jcsd
  3. Jul 7, 2007 #2
    I dont know what retraction is, but where the refraction is concerned, you can use snell's law ([tex]\mu sin\theta =k[/tex]) and look at the different definitions for the coefficient of refraction ([tex]\mu[/tex]) (k is a constant).

    There is a definition which takes the speeds of the waves into account (mu1/mu2=c2/c1).

    They have given you the wavelength and frequency for this purpose. The relation between them is [tex]\nu =\frac{c}{\lambda}[/tex] where the symbols have their usual meanings.
     
  4. Jul 7, 2007 #3
    can you just help me out ... wats my U or my cooeffeciants for my refraction...and whats my mu1/mu2?? please im doing corispondants so ive never learned physics from a teacher and this lowsy book stinks...
     
  5. Jul 7, 2007 #4
    sin25/sin35=0.74 then wat...is it 0.74 m/s which is my speed of my new wave in the second medium?? im just rlly confused..please help
     
  6. Jul 7, 2007 #5
    wat is the speed of the waves from the second source in the original medium?

    wat is the is trhe speed of the reflected waves from the first source in the orignal medium?
     
  7. Jul 7, 2007 #6
    ok also is the mu1/mu2 is that m=75/96=0.78 and my 0.74 so thats mu1/mu2 so thats 0.74/0.78 which equals 0.948???
     
  8. Jul 8, 2007 #7
    Ok. Just hang on a second. First thing you should do is look up "Snell's Law" and "Wave Number".
    Secondly, what exactly is the question?
     
  9. Jul 8, 2007 #8
    two vibrating sources emit waves in the same elastic medium. the first source has a frequency of 25 hz, while the frequency of the second source is 75hz. waves from the first source have a wavelength of 6.9 m. they reflect from a barrier back into the original medium, with an angle of relfection of 25 degrees. waves from the second source refreact into a different medium with an angle of incidence of 35 degrees. the speed of the refracted waves is observed to be 96 m/s.

    wat is the speed of the waves from the second source in the original medium?

    wat is the is trhe speed of the reflected waves from the first source in the orignal medium?

    Will the angle of the refraction of the waves from the second source be greater than, less than, or equal to 35 degree as they enter the different medium?

    wat is the wavelength of the waves from the second source in the orignal medium?

    wat is the wavelength of the waves from the second source in the different medium?

    ALSO i wanna know wat the constant k's units are and wat does this constant tell me?
     
  10. Jul 8, 2007 #9
    heres my pic
     

    Attached Files:

  11. Nov 15, 2007 #10
    dude i am also stuck on this question can you lend a hand?
     
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