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!

How to find constants of motion from this hamiltonian?

  1. Oct 8, 2012 #1
    Given H=p^2/2 - 1/(2q^2)
    How to show that there is a constant of motion for this one dimensional system D=pq/2 - Ht ?

    I tried doing it in my usual way i.e. p'=-∂H/∂q and q'=∂H/∂p and then finding the constants of motion but that doesn't match with what I have to show.

    Please guide me as to how to proceed?
     
  2. jcsd
  3. Oct 8, 2012 #2
    You can definitely use Hamilton's equations to show that D is a constant of motion. Are you sure you did calculate [itex]\dot{D}=\frac{d D}{dt}[/itex] correctly?
     
  4. Oct 8, 2012 #3

    vela

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Education Advisor

    You need to show your work so we can see where the problem might lie.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook