(7)

where

Qr = Σ (X ∂x+ Y ∂y+ Z ∂z).
∂qr ∂qr∂qr

(8)

The quantities Q1, Q2, ... are called the generalized components of force acting on the system.

Comparing (6) and (7) we find

ṗ1 − ∂Τ= Q1,   ṗ2 − ∂Τ= Q2, ... ,
∂q˙1 ∂q˙2

(9)

or, restoring the values of p1, p2, ...,

d (∂Τ ) −∂Τ = Q1,  d (∂Τ ) −∂Τ = Q2, ...
dt ∂q˙1∂q1 dt∂q˙2 ∂q2