Page 212 - Schaum's Outline of Theory and Problems of Applied Physics

CHAP. 16] FLUIDS AT REST 197

16.8. Ethanol has a specific gravity of 0.79. One liter of ethanol weighs
(a) 0.79 N (c) 7.7 N
(b) 1.3 N (d) 12.4 N

16.9. A gallon of water and a gallon of antifreeze solution weigh, respectively, 8.4 and 9.2 lb. The antifreeze solution has
a specific gravity of
(a) 0.095 (c) 0.91
(b) 0.80 (d) 1.1

16.10. The air in a vertical cylinder 20 cm in diameter that is open at the top supports a 20-kg piston. The absolute pressure
on the air is
(a) 0.0064 bar (c) 1.019 bar
(b) 0.062 bar (d) 1.075 bar

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16.11. A restaurant lobster tank is filled with seawater of density 1.03 g/cm to a depth of 60 cm. If there are no lobsters in
the tank, the gauge pressure on its bottom is
(a) 6.1 Pa (c) 6.1 kPa
(b) 0.62 kPa (d) 107.4 kPa

16.12. Six lobsters are put in the tank of Question 16.11 and enough water is removed to keep its depth at 60 cm. The gauge
pressure on the tank bottom is now
(a) smaller (c) greater
(b) the same (d) any of the above, depending on the mass of the lobsters

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16.13. A 20-g spoon is put into a dish filled with water to the brim, and 3.0 cm of water overflows. The weight of the
spoon in the water is
(a) 0.03 N (c) 0.20 N
(b) 0.17 N (d) 0.23 N

16.14. A wooden plank 2.5 m long, 40 cm wide, and 60 mm thick floats in water with 15 mm of its thickness above the
surface. The plank’s mass is
(a) 15 kg (c) 60 kg
(b) 45 kg (d) 441 kg

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16.15. A force of 1000 lb is needed to raise a 12.9 ft concrete block (weight density 140 lb/ft ) to the surface of a freshwater
lake. The force needed to lift the block out of the water is
(a) 700 lb (c) 1140 lb
(b) 1062 lb (d) 1800 lb

16.16. A hydraulic press has an input piston 10 mm in diameter and an output piston 50 mm in diameter. An input force of
80 N gives an output force of
(a) 3.2 N (c) 400 N
(b) 16 N (d) 2000 N

16.17. Pushing the input piston of the press in Question 16.16 through 40 mm causes the output piston to be pushed by
(a) 1.6 mm (c)40 mm
(b) 8 mm (d) 200 mm