Lagrangian and Hamiltonian equations of motion

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SUMMARY

The discussion focuses on deriving the equations of motion for a particle using Lagrangian, Newtonian, and Hamiltonian mechanics. The participant starts with a force defined as F = Ct, where C is a constant and t is time. The Lagrangian is established as L = T - V, with kinetic energy T = 1/2 mv^2 and potential energy V = mvx. The final equations derived include L = 1/2 mv^2 + Ctx and Hamiltonian H = 1/2 mv^2 - Ctx, confirming the successful application of these mechanics.

PREREQUISITES
  • Understanding of Lagrangian mechanics and the equation L = T - V
  • Familiarity with Newton's second law, F = ma
  • Basic knowledge of Hamiltonian mechanics and the Hamiltonian function H
  • Concept of potential energy in the context of force fields
NEXT STEPS
  • Study the derivation of Lagrangian equations for different force functions
  • Explore the relationship between Lagrangian and Hamiltonian mechanics
  • Learn about the application of Newton's laws in non-inertial frames
  • Investigate advanced topics in classical mechanics, such as action principles
USEFUL FOR

Students and professionals in physics, particularly those studying classical mechanics, as well as educators looking to explain the connections between different mechanics frameworks.

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Homework Statement


To try and relate the three ways of calculating motion, let's say you have a particle of some mass, completely at rest, then is acted on by some force, where F equals a constant, C, times time. (C*t).
I want to find the equations of motion using Lagrangrian, but also Newton and Hamilton

Homework Equations


I know I need L= T - V
T = 1/2mv^2, where v is x dot
This needs to be altered for the Force equation
I feel PE (V) is just mvx

The Attempt at a Solution


Then if these T and V are correct, I need to solve the DE for Lagrange. That is easy once I know my L equation is correct.
Next, Hamilton.

How would this be done with Newton's equations of motion? Simple I'm sure.

Thanks!
 
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If you're working in one dimension, Newton's second law is just m a = C t, where a is the acceleration. Since F = -dU/dx, we can choose U = - C t x. Then L = 1/2 m v^2 + C t x, and H = 1/2 m v^2 - C t x.
 
Thank you! That did it. All solved.
 

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