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

Average relative velocity in calculating mean free path

  1. Jun 20, 2013 #1
  2. jcsd
  3. Jun 21, 2013 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Try it and see what happens when you use the mean-relative-velocity. ;)
     
  4. Jun 22, 2013 #3
    Thanks Simon,

    I'm not really following. The mean-relative-velocity would be 0 since velocity is a vector. I think I meant to say mean-relative-speed. I would expect the mean-relative-speed to be less than the rms-relative-speed but that's about it.

    Thanks
     
  5. Jun 22, 2013 #4

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Ri-ight - so, look through your notes about mean free path, where it is applied (say: brownian motion) and use your idea of the mean-speed instead of the rms speed. (You'll have to adjust the derivation to account for the difference.) See what you get.

    I could go and just describe in words why the rms speed is preferred etc etc ... but that's a lot of typing when I can just make you do the math. You asked the question: are you prepared to find the answer?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Average relative velocity in calculating mean free path
Loading...