Insights Blog
-- Browse All Articles --
Physics Articles
Physics Tutorials
Physics Guides
Physics FAQ
Math Articles
Math Tutorials
Math Guides
Math FAQ
Education Articles
Education Guides
Bio/Chem Articles
Technology Guides
Computer Science Tutorials
Forums
Intro Physics Homework Help
Advanced Physics Homework Help
Precalculus Homework Help
Calculus Homework Help
Bio/Chem Homework Help
Engineering Homework Help
Trending
Featured Threads
Log in
Register
What's new
Search
Search
Search titles only
By:
Intro Physics Homework Help
Advanced Physics Homework Help
Precalculus Homework Help
Calculus Homework Help
Bio/Chem Homework Help
Engineering Homework Help
Menu
Log in
Register
Navigation
More options
Contact us
Close Menu
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
Homework Help
Advanced Physics Homework Help
Lagrangian of a driven pendulum (Landau problem)
Reply to thread
Message
[QUOTE="Robin04, post: 6129451, member: 544570"] I realized that I didn't really think about the potential energy just accepted it as it is. So let's call ##d## the vertical displacement of the point of support relative to its lowest possible position, and let's put the zero-potential at the lowest possible position of the pendulum. Then the height of the mass above this level is ##h=d+l(1-cos(\phi))##, and ##d=a(1-sin(\gamma t))## If I leave the sine term as it only depends explicitly on time I still have ##U=mga+mgl(1-cos\phi)## I assume I have to leave all the constants too, and this seems so trivial that Landau doesn't even mention it, but I don't really understand why can we do this. I suppose this was also the case with the ##\frac{1}{2}ma^2\gamma^2## term. Oh, so that's what he means by leaving the total derivatives. But I don't understand this either. Why can we leave the total derivatives? I had classical mechanics this semester and my teacher neglected lots of things too, but I don't really see why are the neglected terms less important than the others. What's so special about only time dependent, total derivative or constant terms? I haven't noticed it, thank you! However, they don't discuss why are those terms neglected. [/QUOTE]
Insert quotes…
Post reply
Forums
Homework Help
Advanced Physics Homework Help
Lagrangian of a driven pendulum (Landau problem)
Back
Top