# Lagrangians and P-Conservation

by moonman
Tags: lagrangians, pconservation
 P: 21 I have a problem with a particle experiencing a central force towards some origin, as well as a gravitational force downwards. I've calculated the Lagrangian, and the equations of motion. Now I'm being asked to see if the system follows conservation of angular momentum. How do I do this? I know it has something to do with seeing if the system is invariant of rotation, but how do I check for that?
 P: 214 If $$\frac{\partial L}{\partial q} =0$$ then the conjugate momentum $$\frac{\partial L}{\partial \dot{q}}$$ is a conserved quantity. If that doesn't clear things up, then post what you have for the Lagrangian.
 P: 141 But the conjugate momentum is the same as the angular momentum only in some cases. Compute H and chech if H commutes with J.

 Related Discussions General Physics 0 General Physics 0 Quantum Physics 2 General Physics 19