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Homework Help: Galaxy electromagnetic

  1. Oct 15, 2007 #1
    A distant galaxy is simultaneously rotating and receding from the earth. As the drawing shows, the galactic center is receding from the earth at a relative speed of uG = 1.5e6 m/s. Relative to the center, the tangential speed is vT = 0.3e6 m/s for locations A and B, which are equidistant from the center. When the frequencies of the light coming from regions A and B are measured on earth, they are not the same and each is different than the emitted frequency of 6.400e14 Hz.


    Vt = wr
    fo = fs (1 +- vrel/c)

    No idea where to start
  2. jcsd
  3. Oct 15, 2007 #2


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    Staff Emeritus
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    I am assuming that you have to work out what the measured frequencies of A and B are given their emitted frequency? You have the equation for finding the observed frequency compared to the emitted frequency:

    [tex] f_o=f_s \left(1+\frac{v}{c}\right)[/tex]

    What is the relative velocity of points A and B from the Earth?
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