Solving Classical Mechanics #3d - Momentum p in Jaccobi Function

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Homework Help Overview

The problem involves classical mechanics, specifically focusing on the momentum in the context of the Jacobi function and its relation to the Euler-Lagrange and canonical equations of motion.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to understand the role of momentum in the Jacobi function and questions whether it is correct to focus solely on coordinate x and its derivatives. Other participants express a need for clarification on specific parts of the problem and relate the canonical equations of motion to the Euler-Lagrange equations.

Discussion Status

Participants are exploring different aspects of the problem, with some making progress on specific parts while others seek further clarification. There is an ongoing examination of the relationships between different equations of motion.

Contextual Notes

Some participants mention specific problems from a homework set, indicating that they are working within the constraints of assigned tasks. There is a focus on ensuring that the coordinates match across different formulations of the equations of motion.

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Homework Statement


The problem is number 3d in the following file:
http://phstudy.technion.ac.il/~wn114101/hw/wn2010_hw06.pdf



The Attempt at a Solution


I think the difference comes from the using of the momentum p. In the Jaccobi function, we use only coordinate x and its derivatives.
Is it correct?
 
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And also number 4a ii.
How Do I do that?
thank you
 
O.k
I made some progress.
In 4, i need only help with a)ii
thanks
 
The Euler-Lagrange equations of motion are second order differential equations while the canonical equations of motion are first order differential equations. So in the case of the 1D simple harmonic oscillator (with [itex]m=k=1[/itex]),

[tex] H=\frac{p^2}{2}+\frac{x^2}{2}[/tex]

the canonical equations come from:

[tex] \dot{p}=-\frac{\partial H}{\partial x}=-x[/tex]

[tex] \dot{x}=\frac{\partial H}{\partial p}=p[/tex]

so how can you relate these to the Euler-Lagrange equations of motion:

[tex] \frac{d}{dt}\left(\frac{\partial L}{\partial\dot{x}}\right)-\frac{\partial L}{\partial x}=0[/tex]

for the same problem?EDIT: Fixed the E-L eom so that its coordinates match the Hamiltonian & canonical equations of motion.
 
Last edited:

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