### Month: April 2017

Can Hamiltonian mechanics describe dissipative systems?

## Can Hamiltonian mechanics describe dissipative systems?

TL;DR – Time dependent Hamiltonian mechanics is for conservative forces in non inertial frames, not for non-conservative forces. In a previous post we saw how Hamiltonian and Newtonian mechanics are different as the first cannot describe dissipative systems. Yet, if we allow the Hamiltonian to be time dependent, the system would appear to change its …

Newtonian, Lagrangian and Hamiltonian mechanics are not equivalent

## Newtonian, Lagrangian and Hamiltonian mechanics are not equivalent

TL;DR – Particle under friction is Newtonian, but neither Lagrangian or Hamiltonian. Photon as a particle is Hamiltonian, but neither Lagrangian or Newtonian. After taking a course in advanced mechanics, one is often left with the impression that Netwonian, Lagrangian and Hamiltonian mechanics are all equivalent. Unfortunately, while this is often what a book would …