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Unformatted text preview: virani (sv2339) HW 3 moura (58650) 1 This print-out should have 11 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points Which of the following is a vector quantity? 1. none of these correct 2. density 3. mass 4. speed 5. temperature Explanation: A vector is a quantity with both magni- tude and direction. Temperature, density, and mass do not have direction, so they are scalars rather than vectors. Speed, by defini- tion, is the magnitude of velocity (which is a vector), so it is also a scalar. Therefore the correct choice is none of these. 002 10.0 points When two vectors sum to zero, how must they be related? 1. Both magnitude and direction are the same. 2. The magnitudes are the same; the direc- tions are opposite. correct 3. The magnitudes are different; the direc- tions are opposite. 4. The magnitudes are different; the direc- tions are the same. 5. All are wrong. Explanation: The magnitudes are the same, and the di- rections are opposite. 003 10.0 points Consider position [ x ] = L, time [ t ] = T, ve- locity [ v ] = L / T and acceleration [ a ] = L / T 2 . Find the exponent A in the equation v = a 2 t A x 1. 2 2. 4 3. 1 4. 3 correct Explanation: [ v ] = [ a ] 2 [ t ] A [ x ] L T = parenleftbigg L T 2 parenrightbigg 2 T A L = L 2 L T A- 4 Equating exponents, A- 4 =- 1 A = 3 ....
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This note was uploaded on 11/12/2009 for the course PS 303 taught by Professor Modi during the Spring '08 term at University of Texas at Austin.
- Spring '08