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!

Velocity with relativity

  1. May 13, 2009 #1
    Find the speed of a particle that takes 2.0 y longer than light to travel a distance of 6.7 ly. Answer is wanted in terms of 'c'.

    delta(t)= delta(t0)/(sqrt(1-(v/c)^2)).

    8.7= 1/(sqrt(1-(v/c)^2))-->
    v=0.993372c....which is incorrect, any assistance would be greatly appreciated[/b]
    note: I also tried delta(t) to be 4.7...also incorrect
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. May 13, 2009 #2


    User Avatar
    Homework Helper
    Gold Member

    What is the speed of light in units of light-years per year? It's just one! Light travels one light-year per year.

    The particle travels 6.7 light-years in (6.7 + 2) years, so it's speed in units of light-years per year is ... ?
  4. May 13, 2009 #3
    Thank you so much!! That makes perfect sense. I hate when I over-complicate problems like these. Much appreciated!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Velocity with relativity
  1. Relative velocity (Replies: 3)

  2. Relative velocity (Replies: 3)

  3. Relative velocities (Replies: 1)