RESOLUTION OF FORCES 131 



ity of the wind. It also depends upon certain whirls in the 

 atmosphere, which are not very well understood, but which 

 will be discussed when we consider the weather and its causes. 

 The recording of weather changes, including the measurement 

 of wind velocity, is given in Section 109, Weather Instru- 

 ments. 



References : 



1. 1103 : 106-113. Variation in the Velocity of the Winds. 



2. 1304 : 422. Anemometer, or Wind Measurer. 



a. 1102 : ^4-95. Force and Velocity of the Wind and its 



Measurement. 

 &. 1301 : 99-101. Velocity of Wind. 



c. 1302 : 288-289. Pressure and Velocity of Winds. 



d. 1303 : 37-38. Observation of Winds. 



e. ,1309 : 218. Winds and their Measurements. 



/. 1312 : 376. High Velocity of Winds from Tornadoes. 



g. 1607 : 532. Relation of Wind Pressure to Wind Veloc- 



ity. 



97. RESOLUTION OF FORCES 



In Section 38 we learned that each force acts independently 

 of all other forces which may be acting at the same time. We 

 also learned that the result obtained by two forces could be 

 accomplished by one force properly directed. It will not 

 seem strange, then, to learn that any force may be resolved, 

 or analyzed, into two or more components. The components 

 usually desired are the two forces, which, acting at right angles, 

 could produce the single force under consideration. These 

 forces may be obtained geometrically or graphically. 



The given force should be considered as the hypotenuse of 

 a right triangle. The other forces, that is, the components, 

 are the base and altitude of the right triangle. Since an in- 



