7- Electric Potential Energy-solutions

7- Electric Potential Energy-solutions - gilvin (jg47854)...

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Unformatted text preview: gilvin (jg47854) 7: Electric Potential Energy meyers (21235) 1 This print-out should have 19 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. Thios homwework is due Tuesday, February 22, at midnight Tucson time. 001 (part 1 of 2) 10.0 points Pictured below are 5 different configurations of point charges: + Q + Q 1) R b b Q + Q 2) R b b Q Q 3) R b b + Q 4) b + Q + Q + Q 5) R R b b b Which of the following choices has the high- est potential energy? 1. Configuration (3) and Configuration (5) 2. Configuration (1) and Configuration (5) 3. Configuration (1) 4. Configuration (1) and Configuration (2) 5. Configuration (2) and Configuration (3) 6. Configuration (5) correct 7. Configuration (1) and Configuration (3) 8. Configuration (2) 9. Configuration (3) 10. Configuration (4) Explanation: The potentials of the 5 cases are U 1 = k e Q 2 R U 2 = k e Q 2 R U 3 = k e Q 2 R U 4 = 0 U 5 = k e Q 2 R + Q 2 R + Q 2 2 R = k e 5 2 Q 2 R 002 (part 2 of 2) 10.0 points Which of the following choices has the lowest potential energy? 1. Configuration (4) 2. Configuration (1) and Configuration (5) 3. Configuration (1) and Configuration (2) 4. Configuration (2) correct 5. Configuration (3) 6. Configuration (2) and Configuration (3) 7. Configuration (1) 8. Configuration (5) 9. Configuration (1) and Configuration (3) 10. Configuration (3) and Configuration (5) Explanation: Only U 2 has a negative potential. 003 10.0 points Two alpha particles (helium nuclei), each con- sisting of two protons and two neutrons, have an electrical potential energy of 6 . 5 10 19 J . Given: k e = 8 . 98755 10 9 N m 2 / C 2 , q p = 1 . 6021 10 19 C , and g = 9 . 8 m / s 2 . What is the distance between these parti- cles at this time? Correct answer: 1 . 4196 10 9 m. Explanation: gilvin (jg47854) 7: Electric Potential Energy meyers (21235) 2 Let: U electric = 6 . 5 10 19 J , k e = 8 . 98755 10 9 N m 2 / C 2 , q p = 1 . 6021 10 19 C , q = 2 q p = 3 . 2042 10 19 C , and q n = 0 C . q 1 = q 2 = 2 q p + 2 q n = 2 (1 . 6021 10 19 C) + 2 (0 C) = 3 . 2042 10 19 C U electric = k e q 1 q 2 r r = k e q 1 q 2 U electric = k e q 2 1 U electric = (8 . 99 10 9 N m 2 / C 2 ) (3 . 2042 10 19 C) 2 6 . 5 10 19 J = 1 . 4196 10 9 m . 004 10.0 points A charge moves a distance of 1 . 6 cm in the direction of a uniform electric field having a magnitude of 225 N / C. The electrical potential energy of the charge decreases by 90 . 5043 10 19 J as it moves....
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7- Electric Potential Energy-solutions - gilvin (jg47854)...

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