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

Unclear approximation in relativistic calculation of particle's distance travelled

  1. Sep 20, 2014 #1
    From "Martin & Shaw", regarding problem 3.5 (sometimes it uses natural units "c=1"):

    "The particle has [itex]\gamma = E/m \approx 10[/itex], hence [itex]\tau \approx c[/itex] (?) and the average distance is [itex]d \approx c \gamma \tau \approx 3 \times 10^{-14}m[/itex] if we assume a lifetime for the particle at rest of [itex]10^{-23}[/itex]."

    I don't understand why [itex]\tau \approx c[/itex].
    Since [itex]v = c \sqrt{1 - \frac{1}{\gamma^2}}, v = 0.994 c[/itex] and I would agree that [itex]v \approx c[/itex], not [itex]\tau[/itex].
     
  2. jcsd
  3. Sep 20, 2014 #2

    Dale

    Staff: Mentor

    Hmm, I am with you on that. In natural units where c=1 you get energy and mass in the same units, but not speed and time.
     
  4. Sep 20, 2014 #3

    jtbell

    User Avatar

    Staff: Mentor

    It's probably a typographical error, and it was supposed to say ##v \approx c##. That gives his result for the average distance: ##d = vt = v \gamma \tau \approx c \gamma \tau##.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Unclear approximation in relativistic calculation of particle's distance travelled
  1. Relativistic particles (Replies: 2)

Loading...