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Homework Help: Wave form problem

  1. Mar 13, 2010 #1
    1. The problem statement, all variables and given/known data
    Two buoys are floating in the sea, separated by 5 m. A wave with a wavelength of 15 m travels from left to right along the line between the buoys. The left-most buoy moves vertically up and down as described by the equation y=Acos(ωt). Which equation best describes the motion of the buoy on the right?

    a) y = A cos (wt-pie/2)
    b)y = A cos (wt + 90deg)
    c) y = A cos (wt - 2pie/3)
    d) y = A cos (wt- pie/4)
    e) y = A cos (wt + pie/4)

    2. Relevant equations

    3. The attempt at a solution

    I got my answer as C which is correct but I just guessed by finding the wavenumber and timsing it by 5.. i dont understand what x is in the cosine function for wave form exactly and i dont know how to solve this properly! cheers
  2. jcsd
  3. Mar 13, 2010 #2


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    Homework Helper

    The general equation of a propagating wave is given by,
    y = A*cos(2πt/Τ - 2πx/λ).
    Here T is the period, λ is the wavelength and x is the distance where y is measured.
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