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Homework Help: Laser to Moon

  1. Sep 23, 2007 #1
    1. The problem statement, all variables and given/known data
    How long would it take a laser beam to go to the Moon and back if the distance to the Moon is 3.8 x 10^8m?


    2. Relevant equations
    a=2d/t^2
    d=v1 t + 1/2a t^2

    3. The attempt at a solution
    a=2d/t^2
    9.8m/s(Gravity)=2(7.6x10^8)/t^2
    t^2=15.2x10^8/9.8
    t= 12453.99698 secs

    P.S the answer at the back of the book says 2.6sec
     
  2. jcsd
  3. Sep 23, 2007 #2

    hage567

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    Homework Helper

    Why are you including acceleration? Do you know what the speed of light is?
     
  4. Sep 23, 2007 #3
    photons, being massless, are not affected by gravity.... at least not appreciably for your problem
     
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