GYRO STATIC ACTION 



2 3 



A familiar form of gyrostat is shown in Fig. 8. It consists of a 

 spinning wheel mounted in a metal ring which rests on a pivot 0. 

 The pull of the earth on the wheel and ring produces an unbalanced 

 torque about an axis which is at right angles to the axis of spin, and 

 this torque causes the axis of spin to sweep around the pivot as 

 described in connection with Fig. 7. Precessional motion is illustrated 



floor i 



i 

 i 



Pi 



Fig. 8. 



Fig. 9. 



in the simplest kind of way by the ordinary top. Fig. 9 shows a top 

 spinning about an inclined axis S. The weight of the top together 

 with the reaction of the floor against the point of the top produces a 

 torque the axis of which is at right angles to the plane of the paper 



u 



c 



I 



' 



~<r 



F \ 

 back'z 



: front 



s 





> 



axle 









of spin 







back\ 



l front 

 \—F + 



D 



side view. 



I front \view 



Fig. 10. 



in Fig 9, and the effect of this torque is to cause the axis of spin to 

 sweep around the vertical axis PP (the axis of precession). 



The above discussion furnishes a sufficient basis for the considera- 

 tion of the various practical aspects of gyrostatic action, but it is 

 interesting to see how the precessional motion of the gyrostat in Fig. 



