ENERGY OF FLOWING WATER 67 



where 



w 

 m = mass = -, 



g 



g = gravity acceleration = 32. 16, 

 h = head, 

 v = velocity, 



w = weight of water = 62.4 Ib. per cu. ft. ; 

 thus 



-I 



and 



v = V2gh. 



The quantity of flowing water expressed by the formula: 



q = va\ 



where 



q = quantity; 



v = velocity; 



a = area of stream. 



From the above the following formula for calculating the gross 

 horse-power of a stream or body of flowing water may be computed : 



QXJ/X62.4. 



~550 ' 



in which 



H.P. = gross horse-power; 



Q = discharge of water in cubic feet per sec.; 

 H = gross head in feet. 



The above values are, however, only theoretical and never realized 

 in practice. This is caused by the loss in head due to friction in 

 the water conductors, the nature and value of which will be 

 dealt with under the section on Water Conductors. 



