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Ch6-HW3-solutions

# Ch6-HW3-solutions - louey(cal2859 Ch6-HW3 florin(56930 This...

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louey (cal2859) – Ch6-HW3 – forin – (56930) 1 This print-out should have 15 questions. Multiple-choice questions may continue on the next column or page – Fnd all choices be±ore answering. 001 (part 1 of 2) 10.0 points A two-dimensional ±orce v F = F x ˆ ı + F y ˆ moves a particle to a new location that is vr = r x ˆ ı + r y ˆ ±rom where it was originally located. I± F x = 1 N, F y = 1 N, r x = 1 m, and r y = 2 m, what is the work done on the particle by the ±orce? Correct answer: 1 J. Explanation: The work is given by W = v F · Δ = F x r x + F y r y = (1 N) (1 m) + ( 1 N) (2 m) = 1 J . 002 (part 2 of 2) 10.0 points ²ind the angle between v F and . Correct answer: 108 . 435 . Explanation: Since W = v F · Δ = v v v v F v v v | Δ | cos θ θ = cos 1 W v v v v F v v v | Δ | . v v v v F v v v = r F 2 x + F 2 y = r (1 N) 2 + ( 1 N) 2 = 1 . 41421 N and | Δ | = r r 2 x + r 2 y = R 1 m 2 + 2 m 2 = 2 . 23607 m , so θ = cos 1 b 1 J (1 . 41421 N) (2 . 23607 m) B = 108 . 435 . 003 (part 1 of 6) 4.0 points A lithium nucleus has mass 5 . 1 × 10 27 kg. I± its speed is 0 . 988 c (that is, V/c = 0 . 988), what is the particle energy? Use c = 3 × 10 8 m / s. Correct answer: 2 . 97176 × 10 9 J. Explanation: The particle energy is just the total energy, given by E = γ m c 2 . So we have E = 1 ± 1 p V c P 2 m c 2 = 1 R 1 0 . 988 2 (5 . 1 × 10 27 kg) c 2 = 2 . 97176 × 10 9 J . 004 (part 2 of 6) 4.0 points What is the rest energy? Correct answer: 4 . 59 × 10 10 J. Explanation: The rest energy is just E rest = m c 2 = (5 . 1 × 10 27 kg) c 2 = 4 . 59 × 10 10 J . 005 (part 3 of 6) 4.0 points What is the kinetic energy? Correct answer: 2 . 51276 × 10 9 J. Explanation: The kinetic energy is given by KE = E E rest = 2 . 97176 × 10 9 J 4 . 59 × 10 10 J = 2 . 51276 × 10 9 J . 006 (part 4 of 6) 4.0 points

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louey (cal2859) – Ch6-HW3 – forin – (56930) 2 Next, an electric Force acts on the lithium nucleus and does 4 . 7 × 10 9 J oF work on the particle. Now what is the particle energy? Correct answer: 7 . 67176 × 10 9 J. Explanation: We simply add the work done on the system to the total energy From beFore: E f = E i + W = 2 . 97176 × 10 9 J + 4 . 7 × 10 9 J = 7 . 67176 × 10 9 J . 007 (part 5 of 6) 4.0 points What is the rest energy now?
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Ch6-HW3-solutions - louey(cal2859 Ch6-HW3 florin(56930 This...

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