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SPECIFIC GRAVITY.

21

SPECIFIC GRAVITY.

57. The specific gravity of a substance is the quotient obtained by dividing the weight of a given volume of the substance by the weight of an equal volume of water.

58. This quotient has been ascertained by experiment for a great variety of substances, and some of the more useful results are given in the following

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59. Since a cubic centimeter of pure water weighs 1 gram, a cubic decimeter 1 kilogram, and a cubic meter 1 metric ton, the numbers in a table of specific gravities show

(1) the weight in grams of one cubic centimeter

(2) the weight in kilograms of one cubic decimeter (one liter)

(3) the weight in metric tons of one cubic meter

of any given

substance.

60. From the above statement may be deduced the following

Rules.

1. To find the weight of a substance when its volume is known: Multiply the volume by the specific gravity.

2. To find the volume of a given substance when its weight is known: Divide the weight by the specific gravity.

61. Examples.

143. What is the weight in kilograms of a cubical piece of cast-iron measuring 12 cm each way?

144. What is the weight in kilograms of a cannon-ball of cast-iron 17.5 cm in diameter?

145. What is the diameter of a lead bullet of spherical shape weighing 14 grams?

146. What is the weight of a load of bricks, the number of bricks being 1000, and the dimensions of each 19 cm long, 8.7 cm wide, and 6 cm thick?

147. The front wall of a warehouse extending 15m along the street is of granite, and is supported on iron columns. Find the pressure in metric tons on these columns, supposing the walls to be on the average 50 cm thick and to rise 12.5 m above the columns, and making no allowance for windows.

148. A bottle weighing 254 grams when empty holds

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1.34 liters. What will it weigh when filled with sulphuric acid?

149. A bottle weighs 803 grams when filled with sulphuric ether and 241 grams when empty. What is the capacity of the bottle in liters?

150. What is the weight in kilograms of a maple plank 4.3 m long, 63 cm wide, and 7.9 cm thick?

151. How many cubic centimeters of water would be displaced by a cubic decimeter of white-pine wood floating in it? What fraction of the block would remain above water?

NOTE.

A solid body floating in a liquid sinks far enough to displace its own weight of the liquid.

152. What part of an iceberg floating in the ocean would be under water?

153. A bar of wrought-iron floats in mercury. What part of it is below the surface of the mercury ?

154. A solid floating in water is below water. What is the specific gravity of the solid?

155. A bottle holding just 750 cubic centimeters, and weighing when empty 157 grams, is filled with a certain liquid and is then found to weigh 976.5 grams. Find the specific gravity of the liquid.

156. Wishing to ascertain the specific gravity of a piece of metal weighing 1432 grams, I sink it in a vessel that is just full of water and take it out again. Before this was done the vessel full of water weighed 512 grams, but afterwards it weighed only 357 grams. What was the specific gravity of the metal?

157. A piece of wood 1m long, 30 cm wide, and 10 cm thick, is found to weigh 16.95K. What is the specific gravity of the wood?

m

cm

cm

158. A granite obelisk 1" square at the base, 60 square at the top, and 6m high, terminates in a pyramid 30 high, making the total height of the obelisk 6.30m. What is the weight of this obelisk in kilograms?

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5. 0.38 m.

6. 5.29 m.
7. 0.001 m.

8. 0.048 m. 9. 3.675 in. 10. 4,250 m. 11. 3,500 m. 12. 23,500 m. 13. 9,460 m 14. 9,240 in.

15. 397 m.

16. 720 m.

17. 7.3 m.

18. 50 m.

19. 67.678 m. 20. 649.115 m. 21. 415,990 m. 22. 5.26749 Km. 23. 35,000 m. 24. 86.62 m. 25. 15,480 m. 26. 71 m

Ans.

53. 44.478 A. 54. 2.04724 in. 55. 188.71376 lb. 56. 6,340.08 gal. 57. 22.046 T. 58. 40.2325 Km. 59. 80.94 Ha. 60. 2,265.36 L 61. 15.087 m. 62. 17.50651 63. 618.9g. 64. 88.9056 Kg. 65. 8.75 Km. 66. 21.6 Km.

67. 39 Km.

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68. 1.851 Km.; 75 cm.

69. 47.5 Km.

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120. 19.8 cu. m. 121. 99.7921. 122. 65.7 cm. 123. 10.362 1. 124. 503.1.

125. 399.3.

126. 294.2.

127. 233.5.

128. 185.3.

129. 136.6.

78. 0.625; 0.375.

130. 108.4.

27. 73.50672 Km.

79. 18,000.

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82. 80.

136.

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172.0.

83. 0.869 m.

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84. 129.

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33. 217.5 ca.; 2.175 a.

85. 794 days.

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