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Homework Help: Need help with waves

  1. Nov 7, 2004 #1
    Here's the problem I need some help with!

    Two wires are parallel, and one is directly above the other. Each has a length of 61.3 m and a mass per unit length of 0.0209 kg/m. However, the tension in wire A is 29.8 x 10^2 N, while the tension in wire B is 3.21 x 10^2 N. Transverse wave pulses are generated simultaneously, one at the left end of wire A and one at the right end of wire B. The pulses travel toward each other. How much time does it take until the pulses pass each other?

    I know how to find the velocity of each wave:
    v= sqrt (Tension/mass per length)
    vA=sqrt (2980/.0209)=377.603 m/s
    vB= sqrt (321/.0209)= 123.93 m/s

    I just don't know where to go from here. Thanks!
  2. jcsd
  3. Nov 7, 2004 #2


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    Science Advisor
    Homework Helper

    You did the hard part! Just write the position of the two waves and equate them:

    [tex]v_1 t = L - v_2 t[/tex]

    and solve for t.
  4. Nov 7, 2004 #3
    Thank you!!! I guess I just thought it would be harder than that to figure out the time so I don't know what I was thinking. But thanks!
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