50 MOTION OF A SPINNING BODY
(a) a downward force on the hub will steer the wheel to the left; (b) if the wheel is making a turn to the right and tilting over toward the right, a push forward
on the hub will bring the wheel more nearly upright.
2. The face of a certain wheel is not perpendicular to the shaft to which it
is keyed. Show that when the shaft rotates it tends to precess and the bearings are acted upon by a torque about an axis which is not constant in direction.
32. Change in the Motion of a Ship Produced by Precession of
the Shaft. - Suppose that a wave exerts a torque on a side-wheel
steamer causing the steamer to roll to the starboard.* In Fig.
39, the direction of the angular momentum of the paddle-wheels
and connecting shaft is indicated by h,, and the direction of the
applied torque by L. The direction of the precessional velocity
thereby produced is indicated by wp. The precession causes the
bow to turn to the starboard. The development of the precession