With the same approximation (A*) and (B*) are equivalent to

( C+ a2 ) Q− ac sin α N− μa (a sin α + 2c cos α − ρ sin2 α) + Raρ cos α = 0,
M LL

(A**)

−ac Q+ ( A+ c2 ) sin α N CR + K+ 2μ ( A+ c2 ) cos α
L ML MM

+ μc sin α (a − ρ sin α) − Rcρ cos α = 0.

(B**)

The elimination of L, Q, N will lead to an equation for the determination of n2, and n2 must be positive for the motion to be stable.

If b is the radius of the horizontal circle described by G in steady motion round the centre B,

b = v/μ = (cP − aR) / μ = c sin α − aR / μ,

(10)