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!

Homework Help: Using Four vectors & Special Relativity

  1. May 2, 2013 #1

    My question concerns parts (a), (b) and (c) in the below.


    In part (a) we're asked to find the energy, velocity and momentum of the incoming particle AND then to find gamma, however I know the energy of the incoming particle is simply 3MeV but I'm not sure how to find the velocity without finding gamma first? I'm not sure whether this matters but I found E=3MeV, p=2√2 MeV/c and v=2c/3*√2... Is this right? and γ=3

    Part (b) asks which quantities are conserved - surely this is just energy and momentum? Or is the invariant of energy and momentum?

    Part (c) asks to compute the invariant of the system - I'm guessing 'E' is just the total energy i.e. sum of incoming with rest of stationary and 'p' is the momentum determined in part (a)

    Thanks for any help/confirmation on answers,
  2. jcsd
  3. May 2, 2013 #2
    For part a) it looks like you got it right.

    For part b) you could work it out explicitly to check what the correct answer is.

    For part c) yes, you are right.
  4. May 2, 2013 #3
    Cheers man, I guess your suggestion for part (b) would make sense...

    I'll do that now,
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted