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Unformatted text preview: pasha (sep635) – HW 6-4 – Antoniewicz – (56445) 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 8.0 points Consider an isolated system, by which we mean a system free of external forces. if the sum of the particle energies in the system increases by 30 J, what must have been the change Δ U in the system’s potential energy? Correct answer:- 30 J. Explanation: By conservation of energy, we know that Δ E particle + Δ U = 0 , so we can write 30 J + Δ U = 0 ⇒ Δ U =- 30 J . 002 (part 1 of 5) 2.0 points The figure below shows the path of a comet orbiting a star. A B C D E Rank-order the locations on the path in terms of the magnitude of the comet’s mo- mentum at each location, starting with the location at which the magnitude of the mo- mentum is the largest. 1. | ~ p E | > | ~ p D | > | ~ p C | > | ~ p B | > | ~ p A | correct 2. | ~ p E | = | ~ p D | > | ~ p C | > | ~ p B | = | ~ p A | 3. | ~ p A | = | ~ p B | = | ~ p C | = | ~ p D | = | ~ p E | 4. | ~ p D | > | ~ p E | > | ~ p C | > | ~ p B | > | ~ p A | 5. | ~ p A | > | ~ p B | > | ~ p C | > | ~ p D | > | ~ p E | Explanation: Momentum increases as the comet gets closer to the Sun; therefore | ~ p E | > | ~ p D | > | ~ p C | > | ~ p B | > | ~ p A | . 003 (part 2 of 5) 2.0 points Rank-order the locations on the path in terms of the comet’s kinetic energy at each location, starting with the location at which the kinetic energy is the largest. 1. K D > K E > K C > K B > K A 2. K A > K B > K C > K D > K E 3. K E > K D > K C > K B > K A correct 4. K E = K D > K C > K B = K A 5. K E = K D = K C = K B = K A Explanation: K increases as | ~ v | increases; therefore, K E > K D > K C > K B > K A ....
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This note was uploaded on 11/17/2011 for the course PHY 303K taught by Professor Turner during the Fall '08 term at University of Texas.
- Fall '08