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Unformatted text preview: sanchez (ds28677) homework 07 Turner (58220) 1 This printout should have 12 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. 001 (part 1 of 2) 10.0 points A particle undergoes three displacements. The first has a magnitude of 15 m and makes an angle of 24 with the positive x axis. The second has a magnitude of 8 . 2 m and makes an angle of 151 with the positive x axis. (see the figure below). After the third displacement the particle returns to its initial position. 151 24 1 5 m 8 . 2 m Find the magnitude of the third displace ment. Correct answer: 12 . 0081 m. Explanation: Given : bardbl vector A bardbl = 15 m , a = 24 , bardbl vector B bardbl = 8 . 2 m , and B = 151 . C A B A B C C Since vector A + vector B + vector C = 0 , we have vector C = vector A vector B . The components of the third displacement vector C are C x = A x B x = A cos A B cos b = (15 m) cos24 (8 . 2 m) cos151 = (13 . 7032 m) ( 7 . 17188 m) = 6 . 5313 m and C y = A y B x = A sin A B sin b = (15 m) sin24 (8 . 2 m) sin151 = (6 . 10105 m) (3 . 97544 m) = 10 . 0765 m . The magnitude of vector C is bardbl vector C bardbl = radicalBig C 2 x + C 2 y = radicalBig ( 6 . 5313 m) 2 + ( 10 . 0765 m) 2 = 12 . 0081 m . 002 (part 2 of 2) 10.0 points Find the angle of the third displacement (mea sured from the positive x axis, with counter clockwise positive within the limits of 180 to +180 ). Correct answer: 122 . 95 . Explanation: tan C = C y C x C = arctan bracketleftbigg C y C x bracketrightbigg = arctan bracketleftbigg ( 10 . 0765 m) ( 6 . 5313 m) bracketrightbigg = 122 . 95 . 003 (part 1 of 2) 10.0 points Consider two vectors vector A and vector B and their re sultant vector A + vector B . The magnitudes of the vectors vector A and vector B are, respectively, 13 . 1 and 5 . 7 and they act at 120 to each other. sanchez (ds28677) homework 07 Turner (58220)...
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This note was uploaded on 04/07/2011 for the course PHY 303K taught by Professor Turner during the Spring '08 term at University of Texas at Austin.
 Spring '08
 Turner
 Physics, Work

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