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Homework Help: Calculation on Romer's theory of the speed of light

  1. May 2, 2010 #1
    1. The problem statement, all variables and given/known data
    c=2.998 × 108 m/s
    t= 20.5 min (1230s)
    x= ?

    2. Relevant equations
    my guess would be the standard velocity equation, v= x/t (x=vt)
    but it appears i am wrong, is there another formula that includes velocity and time?

    3. The attempt at a solution
    x= (2.998 × 108 m/s)*(20.5*60)
    x= (2.998 × 108 m/s)*1230
    x= 3.68751 x 1011 meters
    x= 368754000 km
  2. jcsd
  3. May 3, 2010 #2


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    Science Advisor
    Homework Helper

    Hi Gothy! :smile:

    Hint: if a lighthouse flashes once a second, what is the difference between the time between the flashes as observed by someone moving towards it at speed v, and by someone else moving away at speed v? :wink:
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