280 THE MECHANICAL POWERS. 



RULE. Multiply the power by its distance from the ful- 

 crum, and divide the product by the weight, and the quo- 

 tient is the distance the weight must be placed from the 

 fulcrum, or, the shortest arm of the lever. 



EXAMPLE. What distance must a weight of 800 Ibs. be 

 placed from the fulcrum, to be raised by a power of 150 Ibs. 

 placed 8 feet from the fulcrum ? 



SOLUTION. 150 Ibs., the power, x 96 inches, its distance 

 from the fulcrum, = 14400 -r- 800 Ibs., the weight,=18 inches. 

 Ans. 



To find the power required to raise a given weight / the 

 distances of the weight and the power from the fulcrum 

 being given. 



RULE. Multiply the weight by its distance from the ful- 

 crum and divide the product by the distance of the power 

 from the fulcrum. 



EXAMPLE. "What power will raise a weight of 600 Ibs. 

 20 inches from the fulcrum, applied 8 feet from the ful- 

 crum ? 



SOLUTION. 600 Ibs., weight, x 20 inches, distance of weight 

 from fulcrum, 12000-^-96 inches, distance of power from 

 fulcrum, =125 Ibs. Ans. 



To find the weight , at a given distance from the fulcrum, 

 a given power at a given distance from the fulcrum will 

 raise. 



RULE. Multiply the power by its distance from the ful- 



