Page:Popular Science Monthly Volume 75.djvu/40

36 spin-momentum produced by an unbalanced torque T' would be completely absorbed by the precessional motion of the spinning wheel as its axis of spin turns in the direction of the curved dotted arrow P', and the spin-momentum produced by an unbalanced torque T" would

be completely absorbed by the precessional motion of the spinning wheel as its axis of spin turns in the direction of the curved dotted arrow P".

To completely hinder the rolling motion of a ship in this way would require the use of a very large wheel rotating at high speed. Thus a rolling torque (T' or T" in Fig. 31) equivalent to 200 tons placed 10 feet to one side of the axis of the ship and continuing for only one tenth of a second would represent the whole amount of spin-momentum