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Unformatted text preview: valdez (vv689) – 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 moved along a straight line at a constant velocity of 100 km/h. 5. The dragster rounded the curve at a con stant 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. The mass is traveling at a constant veloc ity, therefore it has no acceleration. 2. 3. 4. 5. 6. 7. 8. correct 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 . valdez (vv689) – 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. 584000 m/s 2. 2054.6 m/s 3. 2045.8 m/s 4. 1022 . 9 m / s correct 5. 8 . 83789 × 10 7 m / s 6. 3 . 68245 × 10 6 m / s 7. None of these 8. 61374 . 2 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 09/26/2010 for the course PHY 58230 taught by Professor Svhets during the Spring '10 term at University of Texas.
 Spring '10
 SVHETS

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