# Tagged Questions

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### Does mass equal angular momentum?

At the wikipedia pages for angular momentum ($L$) and moment of inertia ($I$) we find the equations: $$L=I \omega$$ $$I=m r^2$$ where $m$ is mass and $r$ is the distance between said mass and ...
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### The exact definition of conjugate momentum density

After checking various websites, I've seen the conjugate momentum density defined as either: \begin{align*} P_r ~=~ \frac{\partial \mathcal{L}}{\partial \dot{A}_r} \end{align*} or \begin{align*} P_r ...
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If momentum is, $$p = \frac{\partial \mathcal{L}}{\partial \dot{q}}$$ and force is, $$F = \frac{dp}{dt}$$ and by Euler-Langrange equations, $$\frac{d}{dt}\frac{\partial \mathcal{L}}{\partial ... 1answer 104 views ### Hamilton-Jacobi formalism and on-shell actions My question is essentially how to extract the canonical momentum out of an on-shell action. The Hamilton-Jacobi formalism tells us that Hamilton's principal function is the on-shell action, which ... 0answers 81 views ### Lagrangian with vanishing conjugate momentum, independent variables Given a Lagrangian density \mathcal L(\phi_r,\partial_\mu\phi_r,\phi_n,\partial_\mu\phi_n), for which we find out that for some \phi_n its conjugate momentum vanishes: ... 3answers 2k views ### What is canonical momentum? What does the canonical momentum \textbf{p}=m\textbf{v}+e\textbf{A} mean? Is it just momentum accounting for electromagnetic effects? 1answer 124 views ### Non-relativistic Kepler orbits Consider the Newtonian gravitational potential at a distance of Sun:$$\varphi \left ( r \right )~=~-\frac{GM}{r}. I write the classical Lagrangian in spherical coordinates for a planet with mass ...
The momentum $m v$ of a particle is formally the same as the derivative its translational kinetic energy $\frac{1}{2} m v^2$ with respect to $v$. Similarly the angular momentum $I \omega$ is the ...