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Unformatted text preview: Zzztayloe, Rex Homework 10 Heinz 81204 Nov 04, 2004 1 This printout should have 15 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. The due time is Central time. 001 (part 1 of 1) 10 points A 1 . 2 m wide by 2 . 0 m long water bed weighs 1084 N. Find the pressure that the water bed exerts on the floor. Assume that the entire lower surface of the bed makes contact with the floor. Correct answer: 451 . 667 Pa. Explanation: Basic Concepts: P = F A A = wl Given: F g = 1084 N w = 1 . 2 m = 2 . 0 m Solution: P = F g w = 1084 N (1 . 2 m)(2 m) = 451 . 667 Pa 002 (part 1 of 1) 10 points A piston A has a diameter of 0 . 79 cm, as shown. A second piston B has a diameter of 3 . 2 cm. A B 440 . 2 N F In the absence of friction, determine the force ~ F necessary to support the 440 . 2 N weight. Correct answer: 26 . 829 N. Explanation: Basic Concepts: P = F A A = r 2 Given: r A = . 79 cm 2 = 0 . 395 cm r B = 3 . 2 cm 2 = 1 . 6 cm F g,B = 440 . 2 N Solution: P A = P B F A A A = F g,B A B F A r 2 A = F g,B r 2 B F A = F g,B r 2 A r 2 B = (440 . 2 N)(0 . 395 cm) 2 (1 . 6 cm) 2 = 26 . 829 N downward. 003 (part 1 of 2) 5 points A submarine is at an ocean depth of 178 m. Assume that the density of sea water is 1 . 025 10 3 kg / m 3 and the atmospheric pressure is 1 . 01 10 5 Pa. The acceleration of gravity is 9 . 81 m / s 2 . a) Calculate the absolute pressure at this depth. Correct answer: 1 . 89083 10 6 Pa. Explanation: Basic Concept: P = P + gh Zzztayloe, Rex Homework 10 Heinz 81204 Nov 04, 2004 2 Given: h = 178 m sea water = 1 . 025 10 3 kg / m 3 g = 9 . 81 m / s 2 P = 1 . 01 10 5 Pa Solution: P = 101000 Pa + (1025 kg / m 3 ) (9 . 81 m / s 2 )(178 m) = 1 . 89083 10 6 Pa 004 (part 2 of 2) 5 points b) Calculate the magnitude of the force ex erted by the water at this depth on a cir cular submarine window with a diameter of 27 . 9 cm....
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 Fall '09
 WOODAHL
 Physics, Work

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