17_InstSolManual_PDF_Part15

17_InstSolManual_PDF_Part15 - unstable orientation. (d) The...

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Solve: and toward the charge. 17.45. Set Up: The force on a charge q that is in an electric field is Solve: (a) The force on is to the right. The force on is to the left. The net force on the dipole is zero. (b) The axis is at the midpoint of the line connecting the charges, and perpendicular to the plane of the figure. The torque is zero when each force, and has zero moment arm. This is the case for and as shown in Figure 17.45a and b. Figure 17.45 (c) For slightly greater than zero, as shown in Figure 17.45c, the torque on the dipole is clockwise and is directed so as to return the dipole to the equilibrium position. For slightly less than zero the torque is counterclockwise and again tends to rotate the dipole back to its equilibrium position. The position of Figure 17.45a is a sta- ble orientation. For slightly less than (Figure 17.45d), the net torque on the dipole rotates it away from the equilibrium position. The same is true for slightly greater than The position of Figure 17.45b is an
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Unformatted text preview: unstable orientation. (d) The electric field of the dipole is directed from the positive charge and toward the negative charge. Thus, in Fig-ure 17.45a the electric field of the dipole is to the left, opposite to the direction of the external field. Reflect: For any orientation of the dipole the net force on the dipole is zero. But only for and is the net torque zero. u 5 180 u 5 0 u 5 180 180. u u 5 180 180 u u 5 0 u u (a) F 1 F 1 F 2 F 2 (b) (c) (d) 2 q 1 q 1 q F 1 F 2 F 1 F 2 1 q 1 q 2 q 2 q 2 q E E E E u 5 180, u 5 0 F 2 , F 1 F 2 5 qE , 2 q F 1 5 qE , 1 q F S 5 q E S . E S 2 2.00 m C E 5 1.04 3 10 7 N / C, E x 5 E 1 x 1 E 2 x 1 E 3 x 5 E 2 1 2 E 1 cos 53.1 5 1.04 3 10 7 N / C E y 5 E 1 y 1 E 2 y 1 E 3 y 5 E 2 5 1 8.99 3 10 9 N # m 2 / C 2 2 2.00 3 10 2 6 C 1 0.0600 m 2 2 5 4.99 3 10 6 N / C E 1 5 E 3 5 1 8.99 3 10 9 N # m 2 / C 2 2 5.00 3 10 2 6 C 1 0.100 m 2 2 5 4.49 3 10 6 N / C Electric Charge and Electric Field 17-15...
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This note was uploaded on 03/06/2009 for the course PHYS 114 taught by Professor Shoberg during the Spring '07 term at Pittsburg State Uiversity.

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