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Homework Help: Power required to generate waves

  1. Mar 2, 2009 #1
    1.
    Determine the speed of transverse waves on
    a string under a tension of 73 N if the string
    has a length of 2.1 m and a mass of 5.9 g
    Answer= 161.1925893 m/s

    I have a problem with the second part of the question:
    Calculate the power required to generate
    these waves if they have a wavelength of 29 cm
    and an amplitude of 7.3 cm. Answer in units
    of kW.


    2. Velocity= Square Root [Tension/(mass/length)]

    Energy= 2 pi^2 mf^2 A^2
    A-amplitude
    m-mass
    f- frequency

    Power= Energy/time

    3. I found the frequency by taking the velocity/wavelength and then found the energy using the above equation. I tried to find a value for time by taking the inverse of the frequency (period) and then plugging the values into P=E/t, but was not correct
     
  2. jcsd
  3. Mar 3, 2009 #2

    LowlyPion

    User Avatar
    Homework Helper

    P = ΔE / Δt

    From your Energy equation.

    E = 1/2*μ*λ*ω2A2

    μ = .0059/2.1 = .00281

    And your t can be found by λ/ν

    making it

    P = 1/2*μ*ν*ω2A2

    What did you calculate?
     
  4. Mar 3, 2009 #3
    Thanks, that worked. It ended up being 14.72 kW
     
  5. Sep 12, 2011 #4
    Hey I have a problem similar to this one. What is the value for the lowercase omega (w)?
    I looked everywhere but I dont know how to find it
     
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