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: Calculation of momentum of relativistic particles

  1. Apr 20, 2012 #1
    1. The problem statement, all variables and given/known data
    A particle of mass M decays at rest into a massless particle and another particle of mass m. The magnitude of the momentum of each of these relativistic particles is:

    2. Relevant equations

    E = γmc2; p=γmv

    3. The attempt at a solution
    Pf-Pi = 0; but the particle is at rest, so pi = 0; and the momentum of massless particle = 0;
    unable to start up with exact condition. Tried equating initial and final energies also, but not getting the right answer. Please help.
  2. jcsd
  3. Apr 20, 2012 #2

    George Jones

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    This isn't correct. Look in your notes and/or text for the relationship between energy and momentum for a massless particle.
  4. Apr 20, 2012 #3
    No, I tried the relation E2 = m2c4+p2c2 also, am not getting right answer. There are no explanations of this in my text graduation text books. These are pg level questions.

    I did substitute E2 = M2c4 (initial energy) and onto r.h.s, p2c2+m2c4+p2c2 - p2c2 is the kinetic energy of the massless particle and m2c4+p2c2 for the particle of mass m.

    Please give a solution if possible, am taking so much time to google n check. I am already running out of time for my entrance exam next week.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook