Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Physics Relativity Question-Train at Relativistic Speeds

  1. Sep 13, 2010 #1
    1. The problem statement, all variables and given/known data

    Train Direction---------->


    Andy Train Mike



    Andy and Mike are on a train travelling at relativistic speeds. They both stike a matchstick at the instance shown where Andy and Mike are equal distances from her. What will she observe?

    a) She will see the light from Andy first
    b) She will see the light from Mike first
    c) She will see the light from Andy and Mike simultaneously because she is equal distances from them
    d)She will see the light from Andy and Mike simultaneously because light travels at the same speed in all frames of references

    2. Relevant equations

    3. The attempt at a solution

    I thought it was D, but the teacher reckons it was A. Would someone please explain why I would be wrong?
  2. jcsd
  3. Sep 13, 2010 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Realize that Andy and Mike strike their matches at the same time according to train clocks. But Angela, on the platform, will disagree. According to her, they struck their matches at different times.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook