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Unformatted text preview: perez (nap563) HW01 Tsoi (58160) 1 This printout should have 24 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. 001 10.0 points A mass attached to a spring oscillates back and forth as indicated in the position vs. time plot below. P x t At point P, the mass has 1. positive velocity and negative accelera tion. correct 2. positive velocity and positive accelera tion. 3. negative velocity and negative accelera tion. 4. negative velocity and positive accelera tion. 5. zero velocity and zero acceleration. 6. negative velocity and zero acceleration. 7. zero velocity but is accelerating (posi tively or negatively). 8. positive velocity and zero acceleration. Explanation: The velocity is positive because the slope of the curve at P is positive. The acceleration is negative because the curve is concave down at P. 002 10.0 points Consider three position curves between time points t A and t B . s B s A B A t A t B 3 2 1 t s Choose the correct relationship among quantities v 1 , v 2 , and v 3 . v = v A + v B 2 when a is a constant. 1. v 1 > v 2 > v 3 2. v 1 < v 2 < v 3 3. v 1 = v 2 = v 3 correct Explanation: The average velocity of an object is v = displacement time = s B s A t B t A . All three curves have exactly the same change in position s = s B s A in exactly the same time interval t = t B t A , so all three average velocities are equal: v 1 = v 2 = v 3 . 003 (part 1 of 2) 10.0 points Consider the positiontime graph for a squir rel running along a clothesline. b b b b b b 1 2 3 4 5 1 2 3 4 1 2 time (s) position(m) What is the squirrels displacement at the time t = 4 . 0 s? Your answer must be within 5.0% Correct answer: 1 m. Explanation: perez (nap563) HW01 Tsoi (58160) 2 Let : x f = 1 m and x i = 0 m . The displacement is x = x f x i = ( 1 m) (0 m) = 1 m . 004 (part 2 of 2) 10.0 points What is the squirrels average velocity during the time interval between 0.0 s and 4.0 s? Your answer must be within 5.0% Correct answer: . 25 m / s. Explanation: Let : t = 4 . 0 s . v avg = x t = 1 m 4 s = . 25 m / s . 005 10.0 points The graph shows the velocity v as a function of time t for an object moving in a straight line. t v t Q t R t S t P Which graph shows the corresponding dis placement x as a function of time t for the same time interval? 1. t x t Q t R t S t P 2. None of these graphs is correct. 3. t x t Q t R t S t P 4. t x t Q t R t S t P 5. t x t Q t R t S t P 6. t x t Q t R t S t P 7. t x t Q t R t S t P correct 8. t x t Q t R t S t P 9. t x t Q t R t S t P Explanation: The displacement is the integral of the ve locity with respect to time: vectorx = integraldisplay vectorv dt....
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This note was uploaded on 03/17/2010 for the course PHY 303K taught by Professor Turner during the Spring '08 term at University of Texas at Austin.
 Spring '08
 Turner
 Physics, Mass

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