58. Three charges q, =+ 100µC, q2 =- 50µC,and q3 =+ 60µC are set on each corner of an equilateral triangle of side 1 meter. Determine the electrostatic force of q4. a. 58.58 N b. 39.23 N 93 92

What is the resultant magnitude and direction of the force on a 5.9 µC charge situated on the y-axis, 5.3 cm from the point of origin, due to a pair of 4.3 µC charges located on the x-axis at opposite sides of the point of origin, each at distance of 4.4 cm from the point of origin? a. 17.2 N b. 74.0 N c. 73.0 N d. 76.0 N e. 61.4 N The surfaces of a lipid bi-layer forming the membrane around a cell with a radius of 1.8 µm has a residual charge qr = 10.6x10-15 C on outside of the bi-layer, and the same amount of negative charge on the inside. What is the force in pN (x10-12 N) on a singly-charged positive ion (q =1.6 ×10-1⁹ C) located on the outer surface of this membrane? Hint: Use F = q E = q (o/e) with o = qr/A = qr/ (4π r²) and = 8.85 x 10-12 F.m-1. Answer:

10. Three point charges lie along a straight line as shown in Figure P22.10, where g, 6.00 C, q,-1.50 uC, and -2.00 uC. The separation distances are d, d, 2.00 cm. Calculate the magnitude and direction of the net electric force on (a) q, (b) 9, and (c) q, = 3.00 cm and %3D Figure P22.10

1. A test charge of +2µC is placed halfway between a charge of +6µC and another of +4µC separated by distance 2d = 9 cm. +4uC The free body diagram of q2 from Part 1 should look like this: 9₁ = +4 µC d 35.52 +2μC F3-2 ✔N 92 = +2 μC F₁-2 +6μС X The force on q2 due to q₁ is repulsive and acts to the right. The force on q2 due to q3 is repulsive and acts to the left. F3-2 > F1-2 93 = because 93 91. (a) Calculate the force on the test charge by the +6μC charge. Hint: The force in the positive x-direction is positive and the negative x direction is negative. ✔N (b) Calculate the force on the test charge by the +4µC charge. (c) Calculate the net force on the test charge by both the charges. +6 μC