1. Not finding help here? Sign up for a free 30min 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!

Fundamental Misunderstanding of SR…?

  1. Oct 8, 2016 #1
    1. The problem statement, all variables and given/known data
    A space explorer travels in a spaceship with v = 0.9c. She goes from Earth to a distant star that is 4 light years away (again, measured from Earth). What is the distance measured by the explorer and how long will she say it took her to get there?

    2. Relevant equations
    ##L=\frac {L_0} {\gamma}## , ##\Delta t = \Delta t_0 \gamma##

    3. The attempt at a solution
    I solved the first part perfectly fine and got the answer of ##L = 1.7## light years. When solving for ##\Delta t## I realized that I didn't have ##\Delta t_0##. No problem! I just solved the equation ##\frac {L_0} v## for ##\Delta t_0## and got a value of ##\frac {40} {9}## years. Since ##\gamma \approx 2.3## I just multiplied ##2.3## by ##\frac {40} {9}## and got a value of ##10.2## years. The actual value is 1.9 years, which happens to also be ##\frac {\Delta t_0} {\gamma}## but I don't see why I'm wrong!

    NOTE: I know that there is another solution to this problem and perhaps it is a bit simpler. I would like to focus on whats wrong with my thought process and fix THAT rather than try to adapt to another method of solving.

    EDIT: Figured out my mistake :)
     
    Last edited: Oct 8, 2016
  2. jcsd
  3. Oct 9, 2016 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Well done - what was it?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Fundamental Misunderstanding of SR…?
Loading...