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Homework Help: The Speed of a transverse wave

  1. Aug 9, 2010 #1
    A copper wire, whose cross sectional area is 1.1 x 10 ^ -6 m^2, has a linear density of 7.0 x 10^-3 Kg/m and is strung between two walls. At the ambient temperature, a transverse wave travels with a speed of 46 m/s on this wire. The coefficient of linear expansion for copper is 17 x 10^-6 , and Youngs modulus for copper is 1.1 x 10^11 N/m^2. What will be the speed of the wave when the temperature is lowered by 14 C?

    v = √(F/(m⁄L)) (1)
    F = Y(∆L/L0)A (2)
    ∆L = α.L0.∆T ⇒ ∆L/L0 = α.∆T (3)

    A = 1.1 x 10^-6 m^2
    m/L = 7 x 10^-3 Kg/m
    α = 17 x 10^-6
    Y = 1.1 x 10^11 N/m^2
    v = 46 m/s

    We can write formula (1) such this:

    v = √((Y.α.∆T.A)/(m/L))

    and now substitute all the variables in the above formula for finding ∆T.
    But now I don't know what do I have to do, ∆T2 to find the speed of the wave.
  2. jcsd
  3. Aug 9, 2010 #2
    Please somebody answer my question
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