EXAMPLES. 85 



87. A block of ice, the volume of which is a cubic yard, 

 is observed to float with -fa of its volume above the surface, 

 and a small piece of granite is seen embedded in the ice. 

 Find the size of the stone, the specific gravities of ice and 

 granite being respectively .918 and 2.65. 



Ans. -g^-j of a yard. 



38. A cylindrical glass cup weighs 8 ozs., its external 

 radius is 1 ins., and its height 4 ins. If it be allowed to 

 float in water with its axis vertical, find what additional 

 weight must be placed in it, in order that it may sink. 



/3757T \ 



Ans. (^-. 8) oz. 



\ o4 / 



39. Find the position of equilibrium of a cone, floating 

 with its axis vertical and vertex upwards, in a fluid of which 

 the density bears to the density of the cone the ratio 27 : 19. 



ns. $ of the axis is immersed. 



40. The whole volume of a hydrometer is 5 cu. ins., and 

 its stem is | of an inch in diameter; the hydrometer floats 

 in a liquid A, with one inch of the stem above the surface, 

 and in a liquid B with two ins. above the surface. Compare 

 the specific gravities of A and B. 



Ans. 1280 TT : 1280 2tr. 



41. What volume of cork, specific gravity .24, must be 

 attached to 6 Ibs. of iron, specific gravity 7.6, in order that 

 the whole may just float in water ? 



Ans. ^Wr of a cubic foot. 



42. If a piece of metal weigh in vacuum 200 grs. more 

 than in water, and 160 grs. more than in spirit, what is the 

 specific gravity of spirit ? Ans. . 



43. A piece of metal whose weight in water is 15 ozs., is 

 attached to a piece of wood, which weighs 20 ozs. in vacuum, 

 uud the weight of the two in water is 10 ozs. Find the spe- 

 cific gravity of the wood. Ans. . 



