1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Finding the 4-velocity of a world line

  1. Mar 4, 2012 #1
    Hello! This is my first post, and I was wondering if anyone could help my uncertainty about this problem.

    1. The problem statement, all variables and given/known data
    given an observer's world line, X = 2T and the metric ds2 = -X2dT2 + dX2, find the components of the observer's 4-velocity


    2. Relevant equations
    I'm using the equation that ds2/dτ2 = u = e0


    3. The attempt at a solution
    Taking our equation for ds2 and dividing it by dτ2, I solve for dX2/dτ2 = u2, keeping in mind that this also equals -1, to get that dX2/dτ2 = X2dT2/dτ2 - 1.

    Is the correct way to think about it? And from the observers frame, is her 4-velocity u = ( X2dT2/dτ2 - 1, 0 , 0, 0 )?

    Thanks so much for your help!
     
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted