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Unformatted text preview: Oslund (hno56) – Homework 9 – sai – (58015) 1 This printout should have 28 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Blood of density 756 kg / m 3 that is to be ad ministered to a patient is raised about 0 . 457 m higher than the level of the patient’s arm. How much greater is the pressure of the blood than it would be if the container were at the same level as the arm? The acceleration of gravity is 9 . 8 m / s 2 . Correct answer: 3385 . 82 Pa. Explanation: Let : ρ = 756 kg / m 3 , h = 0 . 457 m , and g = 9 . 8 m / s 2 . Δ P = ρ g h = (756 kg / m 3 ) (9 . 8 m / s 2 ) (0 . 457 m) = 3385 . 82 Pa . keywords: 002 10.0 points The small piston of a hydraulic lift has a crosssectional area of 5 . 2 cm 2 and the large piston has an area of 37 cm 2 , as in the figure below. F 5 . 2 cm 2 area 37 cm 2 What force F must be applied to the small piston to maintain the load of 97 kN at a constant elevation? Correct answer: 13632 . 4 N. Explanation: Let : A 1 = 5 . 2 cm 2 , A 2 = 37 cm 2 , and W = 97 kN . According to Pascal’s law, the pressure ex erted on A 1 must be equal to the one exerted on A 2 . The pressure P 1 = F A 1 must be equal to the pressure P 2 = W A 2 due to the load. F A 1 = W A 2 , so F = A 1 A 2 W = (5 . 2 cm 2 ) (37 cm 2 ) (97000 N) = 13632 . 4 N . 003 (part 1 of 2) 10.0 points Two opentop containers, #1 on the left and #2 on the right, with equal base area A are placed on two scales. The #2 container on the right has an lower diameter twice that of its upper diameter and the height of its lower (larger) diameter is half that of its water height. Both containers are filled with water to the same height H , as shown below. Scale Scale H = 2 h h D = 2 d D = 2 d d left right #1 #2 What is the relationship between the force exerted by the water on the bottom surface of the containers? Oslund (hno56) – Homework 9 – sai – (58015) 2 1. F left = F right correct 2. F left < F right 3. Cannot be determined 4. F left > F right Explanation: The left container is larger than the right container, holds more water, and obviously weights more. However, the force the water exerts on the bottom of the containers is equal since F = P A = ρ g h π D 2 4 F left = F right 004 (part 2 of 2) 10.0 points What is the relationship between the weights exerted by the flasks on the scales supporting the containers? 1. W left = 5 3 W right 2. W left = W right 3. W left = 8 5 W right correct 4. cannot be determined 5. W left = 7 4 W right 6. W left = 7 5 W right 7. W left = 4 3 W right 8. W left = 2 W right 9. W left = 6 5 W right 10. W left = 3 2 W right Explanation: W left = mg = ρ π D 2 4 H g = g ρH π D 2 4 ....
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 Spring '08
 Kaplunovsky
 Physics, Work, Correct Answer

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