# Set up a proton has charge solve a since the charge

• Notes
• 27

This preview shows page 9 - 12 out of 27 pages.

Set Up: A proton has charge Solve: (a) Since the charge is negative, the force and electric field are in opposite directions and the electric field is upward. (b) The charge is positive so the force is in the same direction as the electric field; the force is upward. F 5 0 q 0 E 5 eE 5 1 1.60 3 10 2 19 C 21 2.50 N 2 5 4.00 3 10 2 19 N. E 5 F 0 q 0 5 20.0 3 10 2 9 N 8.00 3 10 2 9 C 5 2.50 N / C. F 5 0 q 0 E . q 5 1 e 5 1 1.60 3 10 2 19 C. F S 5 q E S . r r 5 d " 5 . F r 5 k 0 q 1 q 2 0 1 r r 2 2 5 1 5 k 0 q 1 q 2 0 d 2 , r r . F 5 k 0 q 1 q 2 0 d 2 . r 5 d F 5 k 0 q 1 q 2 0 r 2 . F / 5. F r a / 5 a r 1 / r 2 , r r 5 D / " 3 . 1 1 r r 2 2 5 3 D 2 F r 5 k 0 q 1 q 2 0 1 r r 2 2 5 3 k 0 q 1 q 2 0 D 2 , F r 5 3 F . r r . F 5 k 0 q 1 q 2 0 D 2 . r 5 D F 5 k 0 q 1 q 2 0 r 2 . F r 5 k 0 q 1 r q 2 r 0 r 2 5 k 0 2 q 1 2 q 2 0 r 2 5 4 k 0 q 1 q 2 0 r 2 5 4 F . q 2 r 5 2 q 2 . q 1 r 5 2 q 1 F 5 k 0 q 1 q 2 0 r 2 . 4.27 3 10 2 10 N, F 2 5 k 1 2 e 2 2 r 2 2 5 1 8.99 3 10 9 N # m 2 / C 2 2 4 1 1.60 3 10 2 19 C 2 2 1 1.15 3 10 2 9 m 2 2 5 6.961 3 10 2 10 N F 1 5 k 1 2 e 2 2 r 2 1 5 1 8.99 3 10 9 N # m 2 / C 2 2 4 1 1.60 3 10 2 19 C 2 2 1 1.85 3 10 2 9 m 2 2 5 2.690 3 10 2 10 N q 1 F 2 F 1 q 2 1.85nm 1.15nm Electric Charge and Electric Field 17-9
17.32. Set Up: A proton has charge and mass Solve: (a) The gravity force is downward so the electrical force must be upward. An upward force from a downward electric field requires a negative charge. The charge is (b) 17.33. Set Up: Use the coordinates shown in Figure 17.33. Since the electric field is uniform, the force is constant and the acceleration is constant. and For an electron, and Figure 17.33 Solve: (a) and (b) Reflect: We could also use the work-energy theorem and set the work done by the force equal to the gain in kinetic energy of the electron. 17.34. Set Up: For a point charge, is toward a negative charge and away from a positive charge. Solve: (a) The field is toward the negative charge so is downward. (b) 17.35. Set Up: For a point charge, Solve: 0 q 0 5 Er 2 k 5 1 6.50 3 10 3 N / C 21 0.100 m 2 2 8.99 3 10 9 N # m 2 / C 2 5 7.23 3 10 2 9 C E 5 k 0 q 0 r 2 . r 5 Å k 0 q 0 E 5 Å 1 8.99 3 10 9 N # m 2 / C 2 21 3.00 3 10 2 9 C 2 12.0 N / C 5 1.50 m E 5 1 8.99 3 10 9 N # m 2 / C 2 2 3.00 3 10 2 9 C 1 0.250 m 2 2 5 432 N / C. E S E 5 k 0 q 0 r 2 . v y 5 v 0 y 1 a y t 5 0 1 1 2.84 3 10 14 m / s 2 21 1.5 3 10 2 8 s 2 5 4.26 3 10 6 m / s E 5 1.62 3 10 3 N / C. E y 5 F y 0 q 0 5 2.59 3 10 2 16 N 1.60 3 10 2 19 C 5 1.62 3 10 3 N / C F y 5 ma y 5 1 9.11 3 10 2 31 kg 21 2.84 3 10 14 m / s 2 2 5 2.59 3 10 2 16 N. a y 5 2 y t 2 5 2 1 3.20 3 10 2 2 m 2 1 1.5 3 10 2 8 s 2 2 5 2.84 3 10 14 m / s 2 . y 5 v 0 y t 1 1 2 a y t 2 . 3.20cm y x 1 1 1 1 1 Positive plate Negative plate 2 2 2 2 2 m 5 9.11 3 10 2 31 kg. q 5 2 e 5 2 1.60 3 10 2 19 C v 0 y 5 0. F S 5 m a S . F S 5 q E S E 5 mg e 5 1 1.67 3 10 2 27 kg 21 9.80 m / s 2 2 1.60 3 10 2 19 C 5 1.02 3 10 2 7 N / C mg 5 eE . q 5 2 2.19 3 10 2 5 C. 0 q 0 5 mg E 5 1 1.45 3 10 2 3 kg 21 9.80 m / s 2 2 650 N / C 5 2.19 3 10 2 5 C. mg 5 0 q 0 E . m 5 1.67 3 10 2 27 kg. q 5 1 e 5 1 1.60 3 10 2 19 C F S 5 q E S . 17-10 Chapter 17
17.36. Set Up: For a point charge, Solve: 17.37. Set Up: The electric field of a point charge has magnitude A proton has charge Solve: (a) (b) Reflect: The electric fields inside atoms are very large.