Question

Three charged particles of q1 = 90.0 nC, q,--90.0 nC, and q3 = 45.0 nC are placed on the y-axis, as shown in the figure g, I2 Charge a, has the coordlnates (0, 12.0 cm), a2 has the coordinates (0, -12.0 cm), and a3 Is located at the orlgin. (a) Find the electric potential energy (in 1) of the configuration of the three fixed charges. A fourth particle, with a mass of 1.92 × 10-13 kg and a charge of q4-180.0 nC, ls released from rest at the point (9.00 cm, 0). Find its speed (in m/s) after it has moved freely to a very large distance away (b) m/s

Answer 1

U = q_1 q_2/4 pi elementof_0 d_12 + q_2 q_3/4 pi epsilon_0 d_23 + q_3 q_1/4 pi epsilon_0 d_31 = -90 times 10^- 9 times 90 times 10^- 9 times 9 times 10^9/0.24 - 90 times 10^- 9 times 45 times 10^- 9 times 9 times 10^9/0.12 + 45 times 10^- 9 times 90 times 10^- 9 times 9 times 10^9/0.12 u_i = -30.375 times 10^- 5J u_f = q_1 q_2/4 pi epsilon_0 d_12 + q_2 q_3/4 pi epsilon_0 d_23 + q_3 q_4/4 pi epsilon_0 d_34 + q_4 q_1/4 pi epsilon_0 d_41 + q_1 q_3/4 pi epsilon_0 d_13 + q_2 q_4/4 pi epsilon_0 d_24 = -90 times 10^- 9 times 90 times 10^- 9 times 9 times 10^9/0.24 - 90 times 10^- 9 times