34 ANSWERS TO PRACTICAL QUESTIONS 



39. A specific-gravity bottle holds 1OO gms. of ^vater 

 and ISO gms. of sulphuric acid. Required the density of 

 the acid. Ans. 1.8. 



40. Wliat is the density of a body which weighs 58 gins. 

 in air and 46 gms. in water ? Ans. 4f . 



41. What is the density of a body which iveighs 63 

 guns, in air and 35 gms. in a liquid of a density of .85 ? 

 Ans. 1.9125. 



HYDRODYNAMICS. 



129 1. Two faucets, one 8 feet and the other 4 feet be- 

 low the surface of the water in a cistern, are kept open for 

 a minute. How many times as much water can be drawn 

 from the first as the second ? 



Hence the first delivers rather more than 41$ more than 

 the second. 



2. How much water will be discharged per second from 

 a short pipe having a diameter of 4 inches and a depth 

 of 48 feet below the surface of the ^vater? 



The cross section of the pipe is 16 x .7854 = 12.57 sq. inches, 

 = .087 sq. feet. _ 



v = ^/'2gh = -v/64 x 48 = 55.4 

 55. 4 x. 087 = 4.8 cu ft. 



3. When we pour molasses from a jug, why is the 

 stream so much larger near the nozzle than at some dis- 

 tance from it ? 



Because, according to the law of falling bodies, the farther 

 the molasses fajls the faster it falls. The stream, therefore, 

 becomes smaller as it moves more swiftly, until, at last, it 

 breaks up into drops. 



4. Ought a faucet to extend into a barrel beyond the 

 staves ? 



