Denote by x, y the components of the slight displacement from the central straight line of the centre of a fly-wheel; and let p, q, 1 denote the direction cosines of the axis of a fly-wheel, and r, s, 1 the direction cosines of a link, distinguishing the different bodies by a suffix.
Then with the previous notation and to the order of approximation required,
θ1 = −dq/dt, θ2 = dp/dt,
(1)
h1 = Aθ1, h2 = Aθ2, h3 = K,
(2)
to be employed in the dynamical equations
| dh1 | − θ3h2 + θ2h3 = L, ... |
| dt |
(3)
in which θ3h1 and θ3h2 can be omitted.