238 EXAMPLES. 



7. When the length is 1600 feet, the head 24 feet, and 

 the diameter 5 inches, find the same quantities. 



Ans. (1) 23.69 ft.; (2) 3.628 ft. ; (3) 0.4947 cu. ft. 



8. When the length is 800 feet, the head 5 feet, and the 

 diameter 6 inches, find the same quantities. 



Ans. (1) 4.848; (2) 2.542; (3) 0.499. 



9. When the length is 800 feet, the head 16 feet, and the 

 diameter 6 inches, find the same quantities. 



Ans. (1)15.514; (2)4.548; (3)0.893. 



10. Two pipes of the same length are 3 inches and 

 4 inches in diameter, respectively. Compare the losses of 

 head by friction, (1) when the velocity is the same, and (2) 

 when they deliver the same quantities of water. 



Ans. (1) 1.33 ; (2) 4.21. 



11. Water is to be raised to a height of 20 feet by a pipe 

 30 feet long and 6 inches in diameter. What is the greatest 

 admissible velocity of the water, if not more than 10 per 

 cent, additional power is to be required in consequence of 

 the friction of the pipe ? Ans. 8 feet per second. 



12. Two reservoirs are connected by a pipe 6 inches in 

 diameter and f of a mile long. For the first quarter mile 

 the pipe slopes at 1 in 50, for the second at 1 in 100, while 

 in the third it is level. The head of water over the inlet is 

 20 feet, and that over the outlet 9 feet. Neglecting all loss 

 except that due to surface friction, find (1) the velocity per 

 second, and (2) the discharge in gallons per minute, assum- 

 ing / = 0.0348. Ans. (I) 3.43 ft.; (2) 253 gallons. 



13. A tank of 250 gallons is 50 feet above the street. It 

 is connected with the street main, the head of which is 52 

 feet, by a pipe 100 feet long. (1) Find the diameter of the 

 pipe that the tank may be filled in 20 minutes ; (2) what 

 must the head in the main be to fill the tank in 5 minutes 

 with the pipe ? Ans. (1) 1.6 inches; (2) 82 feet. 



