Three charged particles are placed at the corners of an equilateral triangle of side 1.20 m (see (Figure 1)). The charges are Q1 = 7.6 µC , Q2 = -9.4 µC , and Q3 = -4.8 µC . %3D Figure 1 of 1 y 1.20 m Q2 Q3 1.20 m 1.20 m

Three charges are placed along the x-axis: q1 = 3.00 µC at X1 = -20.0 cm, q2 = -5.00 µC at x2 = 10.0 cm, and q3 = 6.00 µC at x3 = 25.00 cm. Determine the magnitude of the electric field at the origin. O 4 69x106 N/C O 2 96x106 N/C O 6 04x106 N/C O 4.31x106 N/C

60.0 magnitude direction 0.500 mm (a) Red blood cells often become charged and can be treated as point charges. Healthy red blood cells are negatively charged, but unhealthy cells (due to the presence of a bacteria, for example) can become positively charged. In the figure, three red blood cells are oriented such that they are located on the corners of an equilateral triangle. The red blood cell charges are A = 2.30 pC, B = 7.30 pC, and C= -3.90 pC. Given these charges, what would the magnitude and direction of the electric field be at cell A? (1 pC = 1 x 10-¹2 C.) N/C counterclockwise from the +x-axis.

+1.0 uC +4.0 uC -1.0 uC +6.0 µc 13. The drawing shows four charges in which each are placed on the x and y axes. They are all located at the same distance of 5 cm from the origin O. For each of the situations in the drawing, determine the magnitude and direction of the net electric field at the origin. (show each component of the net electric field) (k = 8.99 x 10° Nm2/c2)