Exam_2_09s - Exam 2 Physics 130 Short Answer Section....

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Unformatted text preview: Exam 2 Physics 130 Short Answer Section. Please answer all of the questions. 1. A 2000 kg automobile moves around an unbanked curve of radius 50 m at 30 m/s. What centripetal force is present due to friction. F c = mv 2 r = 2000 kg (30 m / s ) 2 50 m = 36,000 N 2. A 1500 kg elevator that is pulled by a single cable is accelerating downward at 0.2 m / s 2 . What is the tension in the cable? a = 0.2 m / s 2 ma = T mg T = ma + mg = 1500 kg ( 0.2 m / s 2 ) + 1500 kg (9.8 m / s 2 ) = 14, 400 N 3. A golf ball is hit from the ground with a velocity of 40m/s at an angle of 30 degrees. How long does it take to get to its maximum altitude and how far horizontally has it traveled when it reaches its maximum altitude. y i = m y f = ? v iy = 40sin 30 m / s = 20 m / s v fy = m / s a y = g t = ? v fy = v iy + a y t t = v fy v iy a y = 20 m / s 9.8 = 2.04 s x i = x f = ? v ix = 40cos 30 m / s = 34.6 m / s v fx = v ix a x = x f = x i + v ix t + 1 2 a x t 2 x f = + v ix t + = 70.67 m 4. A mass m slides down an incline at constant speed. The incline makes an angle with horizontal. Friction is present. What is the coefcient of friction? N = mg sin N = mg cos mg cos = mg sin = tan 5. A mass of 1000 kg is acted on by three forces: F 1 = 100 i + 250 j 350 k , F 2 = 50 i + 100 j 500 k and...
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This note was uploaded on 09/27/2010 for the course ASD 2456 taught by Professor Jojo during the Spring '10 term at Brooklyn Law School.

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Exam_2_09s - Exam 2 Physics 130 Short Answer Section....

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