VIII 



MUSOLK-MOVKM! N PS 



the place where the man applies (he power. The power 

 necessary to raise the weight is less than the weight just in 

 proportion to the distances of the weight and the power from the 

 fulcrum, so that the lever is a means of increasing power. The 

 end of the lever on which the man exerts the power moves 

 through a greater range than the end on which the weight lies, 

 and just in proportion to the distances of the power and the 

 weight from the fulcrum. So that the lever is a means of 



Fir;. 34. The three classes of levers. 

 . !', fulcrum ; \V, weight ; P, point of application of power. 



changing range of motion, and if the power is applied to the 

 short arm of the lever, of increasing the range of motion. In 

 the human body it is the wide range of motion of the free end 

 of a limb which is the main advantage obtained by the lever 

 mechanism. 



Levers are divided into three classes according to the 

 position of the fulcrum : 



Class I. The fulcrum between the weight and the power. 

 Class II. The fulcrum at one end, and nearer to the 

 weight than to the power. 



