THE INCLINED PLANE 



107 



203. Law for the Second Case. By resolving 

 the force of gravity, or by experi- 

 ment, the following law may be 



established : When a given power 

 acts parallel to the base, it luill 

 support a weight as many 

 times as great as itself as the 

 hoHzontal base of the plane is 

 times as great as its vertical 

 height. 



204. The Third Case. For the third case, the power 

 acting in a direction parallel to neither the length nor the base of 

 the plane, no law can be given. The ratio of the power to the 

 weight may be determined by resolving the force of gravity, as 

 above explained, the construction and measurement being carefully 

 done. 



EXERCISES. 



Remark. The first problem may be read : 



(a.) In a system of pulleys, the weight being supported by two 

 sections of the cord, a power of 25 Ibs. will support what weight ? 



(&.) In an inclined plane, the power acting in the direction of the 

 length of the plane, the height of the plane being 3 ft., what must 

 be the length that the same power may support the same weight ? 



