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Homework Help: Special relativity homework question time dilation

  1. Nov 14, 2011 #1
    1. The problem statement, all variables and given/known data
    You are a passenger on a brand-new spaceship that travels at 95% of the speed of light, i.e.,
    v = 0.95 × c. The spaceship is bound for the star, Altair, at a distance of 17 light years from
    Earth. If the spaceship departs on your 21st birthday, at a speed of v = 0.95c, how old are you
    when the spaceship arrives at Altair?

    2. Relevant equations
    Δtmoving = Δtrest x [square root of (1−v^2/c^2)]

    v= d/t

    3. The attempt at a solution
    I have no idea how to do this problem, in my opinion it appears to be poorly worded, I don't know if the professor means age relative to earth time or age relative to the traveling speed. This is my attempt to find a solution:

    v=d/t v=0.95c --> 0.95c= 17lightyears/ t

    t= d/ v

    t= 17ly/ 0.95 c
    Last edited: Nov 14, 2011
  2. jcsd
  3. Nov 14, 2011 #2


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    Homework Helper

    I sympathize with you; relativity really confused me, too! Even those guys at CERN measuring neutrinos were confused. I remember just enough to know that this question is very well worded - no nonsense about accelerating at the beginning or end to worry about. Just the Earth frame of reference. I think your calc is correct, but you better check here to be sure:
  4. Nov 14, 2011 #3

    Doc Al

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    Staff: Mentor

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