1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Parts of a Wave

  1. Dec 6, 2009 #1
    The displacement of a wave traveling in the positive x-direction is y(x,t) = (3.5 cm)cos(2.7x - 124t), where x is in m and t is in sec. What are the (a) frequency, (b) wavelength (in m), and (c) speed (in m/s) of this wave?



    I don't know how to do this problem at all. I could use some help beginning and solving this problem. Thanks. I don't know how to do harmonics very well.
     
  2. jcsd
  3. Dec 6, 2009 #2

    diazona

    User Avatar
    Homework Helper

    For starters, what do you know about frequency, wavelength, and speed in general?
     
  4. Dec 6, 2009 #3
    They are all linked in the equation:

    v = [tex]\lambda[/tex]f
     
  5. Dec 6, 2009 #4
    The only thing I don't get is how to find any of them if they are all linked with one equation.
     
  6. Dec 6, 2009 #5
    Well, after doing the math (considering I did this right, or I hope I did), I got:

    y(x,t) = Acos((2[tex]\pi[/tex]/[tex]\lambda[/tex])x [tex]\pm[/tex] (2[tex]\pi[/tex]/T)t)

    which led me to

    (a): 124 = 2[tex]\pi[/tex]/T
    T = 2[tex]\pi[/tex]/124 = .05067

    f = 1/T = 1/.05067 = 19.74

    (b): 2.7 = 2[tex]\pi[/tex]/[tex]\lambda[/tex]
    [tex]\lambda[/tex] = 2[tex]\pi[/tex]/2.7 = 2.33 m

    (c): v = [tex]\lambda[/tex]f
    v = (2.33 m)(19.74) = 45.99 m/s



    Please tell me if and where I am wrong, or tell me if that is correct. Bold are the answers.
     
  7. Dec 6, 2009 #6
    That's what I got!
     
  8. Dec 6, 2009 #7
    Well, do you think we are right? I sure as heck hope so!
     
  9. Dec 6, 2009 #8
    Haha, yeah, we're right.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Parts of a Wave
  1. Parts for Project (Replies: 5)

  2. Wave ? (Replies: 3)

  3. Waves (Replies: 2)

Loading...