Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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

    rl.bhat

    User Avatar
    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.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook