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Unformatted text preview: patel (kp9583) HW1 Mackie (20211) 1 This print-out should have 12 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. DEADLINE IS CENTRAL TIME! 001 10.0 points A newly discovered giant planet has an aver- age radius 18 times that of the Earth and a mass 548 times that of the Earth. Calculate the ratio of the new planets den- sity to the Earths density. Correct answer: 0 . 0939643. Explanation: Let : R n = 18 R E and m n = 548 m E . A spherical planet of average radius R has volume 4 3 R 3 , so the density is = m v = m 4 3 R 3 = 3 m 4 R 3 m R 3 . For two planets of respective radii R N and R E and masses m N and m E we have N E = m N R 3 N m E R 3 E = parenleftbigg m N m E parenrightbigg parenleftbigg R N R E parenrightbigg 3 = 548 (18) 3 = . 0939643 . 002 (part 1 of 2) 10.0 points While John is traveling along a straight inter- state highway, he notices that the mile marker reads 234 km. John travels until he reaches the 149 km marker and then retraces his path to the 174 km marker. What is Johns resultant displacement from the 234 km marker? Correct answer:- 60 km. Explanation: Let the initial position be s o = a = 234 km, the second position b = 149 km, and his final position s f = c = 174 km. Thus s = s f- s o = 174 km- 234 km =- 60 km 003 (part 2 of 2) 10.0 points How far has he traveled? Correct answer: 110 km. Explanation: The distance traveled is given by d = | b- a | + | c- b | = | 149 km- 234 km | + | 174 km- 149 km | = 110 km 004 (part 1 of 2) 10.0 points A bug completes one lap along the edge of a...
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- Fall '09