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Homework Help: Question about relativistic motion

  1. Sep 3, 2008 #1
    I have this question .

    There are two bodies in space . Each are moving with a speed of C/2 towards each other . What is the relative speed of one body with respect to the other .

    According to classical view it has to be C but in real it doesnt can any1 tell me how to find the answer .:rolleyes:
  2. jcsd
  3. Sep 3, 2008 #2


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  4. Sep 4, 2008 #3
    u' = (u1 + v1)/(1 - u1*v1/c^2) where u1, v1 are velocities... this reduces to u' = u1 + v1 classically. substitute u1 = c/2, u2 = c/2, etc. and you have your answer.
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