Measuring Water, Speeds, etc. 99 



Method. Multiply the diameter of the 

 ' ' driver ' ' by its number of revolutions and 

 divide the product by the diameter of the 

 "driven." 



4th Problem. Knowing the diameter of the 

 ' ' driver ' ' and ' ' driven ' ' and the number 

 of revolutions of the " driven," it is required 

 to know the revolutions of the " driver." 



Method. Multiply the diameter of the 

 ' ' driven ' ' by its number of revolutions and 

 divide the product by the diameter of the 

 "driver." 



Toothed Wheels. 



To calculate the speed of toothed wheels, 

 the same problems can be applied as for the 

 pulleys. Multiply or divide by the number of 

 teeth instead of by the diameter in inches. 



Example Problem 1 for Pulleys 



Number of revolutions of ' ' driver " . 60 

 Number of revolutions of ' ' driven ' ' . 120 

 Diameter of " driven " . . . . 20" 



Find diameter of " driver." 



20 x 120 - 2400 -r 60 = 40", diameter of 

 "driver." 



