Question

Charges q1, q2, and q3 sit on the corners of a rectangle with sides of 3.00 m and 4.00 m, as shown in the figure below. Charge q4 is placed at the center of the rectangle, at the point (x -2.00 m, y-1.50 m) What is the magnitude and direction (relative to the +x axis) of the net electric field at point P due to the four charges? +y 41 Q2-+2.00 nC 93 = +3.00 nC q -0.500 nC 94 3 m 93 +x 4 m

Answer 1

E_x = due to Q_3 - 9 times 10^9 times 3 times 10^-9/16 + due to Q_4 9 times 10^9 times 0.5 times 10^-9/6.25 times 2/2.5 - due to Q_2 9 times 10^9 times 2 times 10^-9/25 times 4/5 E_x = -1.6875 + 0.576 - 0.576 = -1.6875 E_y = 9 times 10^9 times 1 times 10^-9/9 + 9 times 10^9 times 0.5 times 10^-9/6.25 times 1.5/2.5 - 9 times 10^9 times 2 times 10^-9/25 times 3/5 E_y = 1 + 0.432 - 0.432 = 1 Vertical-bar E Vertical-bar = squareroot (1.6875)^2 + 1^2 = 1.9615 N/C theta = pi - tan^-1 (1/1.6875) = 180 - 30.65 = 149.35 degree with axis