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Homework Help: New to the physics thing and toldly lost help please

  1. Aug 18, 2009 #1
    1. The problem statement, all variables and given/known data

    the speed is doubled and the freq stays the same what happens to the wave length?

    this is my frist day in this class and i have no idlea where to go with this if someone could help me though this and tell me how to fig stuff like this out it would be great

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Aug 18, 2009 #2


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    Homework Helper

    The characteristics of the waves are
    frequency, wavelength, velocity,amplitude and phase.
    Can you find a relation between these quantities?
  4. Aug 18, 2009 #3
    um no i know i sound really dumb right now and i am in this stuff but if your asking for a graph there isnt one the qestion only has the speed doubles the freq stays the same and what happens to the lenght i dont know where to start to figure this out i am sorry i am not askin you to do it for me i am just askin for help on how to do it so i can figure this stuff out
  5. Aug 18, 2009 #4


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    The relation between frequency, wavelength and velocity is
    v = f*λ.
    Ιn this equation, if frequency remains constant, how does the wavelength varies with velocity?
  6. Aug 18, 2009 #5
    i think that it would get longer i am so lost thanks for trying to help me i think i am just going to go talk to the teacher tomorrow
  7. Aug 18, 2009 #6


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    Yes. It doubles.
  8. Aug 18, 2009 #7
    so if the speed or velocity doubles and the wavelength stays constant then the frequency would be halfed?
  9. Aug 18, 2009 #8


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    No, the frequency would not be halved. It would be doubled. Start from this equation:

    v = fλ​

    and ask yourself, if I am going to double the velocity (on the left hand side), how would I change the frequency (on the right hand side), given that the wavelength (lambda) must remain constant?
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