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A.50 Answers to Odd-Numbered Problems 5. (a) 1.59 nN away from the other (b) 1.24 ! 10 36 times larger (c) 8.61 ! 10 $ 11 C/kg 7. 0.872 N at 330° $ 5 N toward the other (b) 8.99 ! 10 $ 7 N away from the other 11. (a) 82.2 nN (b) 2.19 Mm/s i $ 2.70ˆj) kN/C (b) ($ 3.00ˆi $ 13.5ˆj) &N 21. (a) 5.91k e q/a 2 at 58.8° (b) 5.91k e q 2 /a 2 at 58.8° 23. (a) ˆi (b) As long as the charge is symmetrically placed, the number of charges does not 25. 1.59 ! 10 6 N/C toward the rod 27. (a) 6.64ˆ i MN/C (b) 24.1ˆi MN/C (c) 6.40ˆi MN/C (d) 0.664ˆ i MN/C, taking the axis of the ring as the x axis 31. (a) 93.6 MN/C; the near-field approximation is 104 MN/C, about 11% high (b) 0.516 MN/C; the point-charge 33. $ 21.6ˆ i MN/C 37. (a) 86.4 pC for each (b) 324 pC, 459 pC, 459 pC, 432 pC 39. [k e
Qx/(R 2 ( x 2 ) 3/2 ] 41. (a) + + + The field is zero at the center of the triangle. e q ˆ j/a 2 43. (a) 61.3 Gm/s 2 (b) 19.5 &s (c) 11.7 m (d) 1.20 fJ 45. K/ed in the direction of motion i ( 102ˆj) km/s 49. (a) 36.9°, 53.1° (b) 167 ns, 221 ns 2 /qR (b) mv 2 /2 1/2 qR oriented at 135° to the x axis 55. (a) 10.9 nC (b) 5.44 mN 59. 63. $ 707ˆ j mN 65. (a) * 1 % * 2 67. (a) 0.307 s (b) Yes. Ignoring gravity makes a difference of 2.28%. 69. (a) F % 1.90(k e q 2 /s 2 )(ˆ i ( ˆj ( ˆk) (b) F % 3.29(k e q 2 /s 2 ) in the direction away from the diagonally opposite vertex CHAPTER 24 1. (a) 858 N - m 2 /C (b) 0 (c) 657 N - m 2 /C 3. 4.14 MN/C 2 /C 9. (a) $ 6.89 MN - m 2 /C (b) The number of lines entering exceeds the number leaving by 2.91 times or more. 11. $Q /4 0 for S 1 ; 0 for S 2 ; $2Q /4 0 for S 3 ; 0 for S 4 13. E 0 " r 2 15. (a) (Q /24 0 (b) $Q /24 0 17. $ 18.8 kN - m 2 /C 19. 0 if R + d; if R ) d 21. (a) 3.20 MN - m 2 /C (b) 19.2 MN - m 2 /C (c) The answer to (a) could change, but the answer to (b) would stay the 23. 2.33 ! 10 21 N/C 25. $ 2.48 &C/m 2 27. 5.94 ! 10 5 m/s 29. E % #r/24 0 away from the axis 31. (a) 0 (b) 7.19 MN/C away from the center !1 mN (b) !100 nC (c) !10 kN/C (d) !10 kN - m 2 /C 35. (a) 51.4 kN/C outward (b) 646 N - m 2 /C 37. 508 kN/C up 0 A vertically upward in each case if Q ) 0 43. (a) ( 708 nC/m 2 and $ 708 nC/m 2 (b) ( 177 nC and $ 177 nC 45. 2.00 N 0 r radially outward 49. (a) 80.0 nC/m 2 on each face (b) 9.04 kˆ kN/C (c) $ 9.04 kˆ kN/C 51. E % 0 inside the sphere and within the material of the shell. E % k e Q /r 2 radially inward between the sphere and the shell. E % 2k e Q /r 2 radially outward outside the shell. Charge $ Q resides on the outer surface of the sphere. 23 4 0
√R 2 $ d 2 Q % 2L √ k(L $ L i ) k e |