Conjugate momenta


Conjugate momenta are dynamical variables that generalize the idea of momentum to generalized coordinates in both Lagrangian and Hamiltonian systems.

Given a Lagrangian LL with nn degrees of freedom over the generalized coordinate q(t)q(t), the ll-th conjugate momentum is defined as

Pl(q,q˙,t)Lq˙l(q,q˙,t)P_{l}(q,\dot{q},t)\equiv \frac{ \partial L }{ \partial \dot{q}_{l} } (q,\dot{q},t)