 Generalized forces

Generalized forces are the coefficients of virtual work in a set of generalized coordinates. A translational coordinate has a force as its coefficient, while an angular coordinate has a torque. A generalized force conjugate to $q_i$ has units of energy divided by the units of $q_i$. Forces not already included in the Lagrangian enter the Euler-Lagrange equations as $d(\partial L/\partial {\dot{q}}_i)/dt-\partial L/\partial q_i=Q_i$.

Generalized forces are a concept from classical mechanics used in the context of Lagrangian and Hamiltonian mechanics. They extend the idea of force beyond merely the conventional forces acting on a system (like gravity, friction, etc.) to include other types of influences that can affect the motion of a system.