hw2 - khounvivongsy (sk27799) Homework 2 Weathers (17104) 1...

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Unformatted text preview: khounvivongsy (sk27799) Homework 2 Weathers (17104) 1 This print-out should have 10 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points A bullet is fired straight up from a gun with a muzzle velocity of 209 m / s. The acceleration of gravity is 9 . 8 m / s 2 . Neglecting air resistance, what will be its displacement after 2 . 1 s? Correct answer: 417 . 291 m. Explanation: Displacement is defined by s = s o + v o t + 1 2 a t 2 . The initial velocity of the bullet is v o = v and its initial displacement is s o = 0 . The gravitational acceleration is negative, so the displacement is s = s o + v o t- 1 2 g t 2 = v t- 1 2 g t 2 = (209 m / s) (2 . 1 s)- 1 2 g (2 . 1 s) 2 = 417 . 291 m . 002 10.0 points A body moving with uniform acceleration has a velocity of 14 . 3 cm / s when its x coordinate is 2 . 83 cm. If its x coordinate 2 . 84 s later is- 8 cm, what is the magnitude of its acceleration? Correct answer: 12 . 7559 cm / s 2 . Explanation: Basic Concept: Kinematic Equations x = x + v t + 1 2 a t 2 Solution: Solving for a , we get a = 2[ x- x- v t ] t 2 =- 12 . 7559 cm / s 2 2 . 003 (part 1 of 2) 10.0 points Throw a ball upward from point O with an initial speed of 72 m / s. The acceleration of gravity is 9 . 8 m / s 2 . t h A y t B h B t A b b b b b b b b b b b b b b b b b b b b b b b b 72 m / s O B A t A is the time to reach its maximum height h A Figure is not drawn to scale. What is the maximum height h A ? Correct answer: 264 . 49 m. Explanation: Basic Concept: Constant acceleration v 2 = v 2 + 2 a ( x- x ) (1) Let : v = 72 m / s and g = 9 . 8 m / s 2 ....
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This note was uploaded on 02/08/2010 for the course PHYS 1710 taught by Professor Weathers during the Spring '09 term at University of North Carolina Wilmington.

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hw2 - khounvivongsy (sk27799) Homework 2 Weathers (17104) 1...

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