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Unformatted text preview: saldana (avs387) – Homework 06 – florin – (58140) 1 This printout should have 12 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points A dragster maintains a speedometer reading of 100 km/h and passes through a curve with a constant radius. Which statement is true? 1. The dragster rounded the curve at a changing speed of 100 km/h. 2. The dragster rounded the curve at a changing velocity of 100 km/h. correct 3. All are wrong. 4. The dragster rounded the curve at a con stant velocity of 100 km/h. 5. The dragster moved along a straight line at a constant velocity of 100 km/h. Explanation: Constant velocity means not only constant speed, but constant direction, so the velocity is changing. A car rounding a curve changes its direction of motion, regardless of its speed. 002 10.0 points A mass slides with negligible friction on a circular track of 1 m radius oriented vertically. Its speed at the position shown in the figure is 3.13 m/s. The acceleration of gravity is 9.8 m/s 2 . v At the position shown in the figure, which of the labeled arrows best represents the di rection of the acceleration of the mass? 1. correct 2. 3. 4. 5. The mass is traveling at a constant veloc ity, therefore it has no acceleration. 6. 7. 8. 9. Explanation: The magnitude of the centripetal is a r = v 2 r = (3 . 13 m / s) 2 1 m ≈ 9 . 8 m / s 2 . The centripetal acceleration is inward − ˆ r and gravity is down − ˆ k . saldana (avs387) – Homework 06 – florin – (58140) 2 a a r g 003 10.0 points Calculate the average speed of the Moon around the Earth. The Moon has a period of revolution of 27.3 days and an average dis tance from the Earth of 3 . 84 × 10 8 m. 1. 61374 . 2 m / s 2. 2054.6 m/s 3. 1022 . 9 m / s correct 4. None of these 5. 3 . 68245 × 10 6 m / s 6. 584000 m/s 7. 2045.8 m/s 8. 8 . 83789 × 10 7 m / s 9. 3688.5 m/s Explanation: Let : T = 27 . 3 d and R = 3 . 84 × 10 8 m ....
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This note was uploaded on 08/30/2010 for the course PHY 58140 taught by Professor Florin during the Spring '10 term at University of Texas.
 Spring '10
 Florin

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