With y = 0, (1), (2), (3) reduce to

(13) u = -qz, v = pz - rx, w = qx;

and, denoting the radius of curvature of the meridian curve of the

rolling surface by [rho],

dx d[theta]

(14) -- = [rho] cos[theta] -------- = -q [rho] cos[theta],

dt dt

dz d[theta]

-- = -[rho] sin[theta] -------- = q [rho] sin[theta];

dt dt

so that

du dq

(15) -- = - -- z - q^2[rho] sin[theta],

dt dt

dv dp dr

(16) -- = -- z - -- x + pq[rho] sin[theta] + qr[rho] sin[theta],

dt dt dt

dw dq

(17) -- = -- x - q^2[rho] cos[theta].

dt dt

Encyclopaedia Britannica, 11th Edition, "Gyantse" to "Hallel" Volume 12, Slice 7 · 第 24 / 53 题