43 21.105. Three charges are placed Figure 21.52 Challenge as shown in Fig. 21.52. The mag- Problem 21.105. nitude of q, is 2.00 uC, but its 91 sign and the value of the charge F 92 are not known. Charge 43 is 4.00 cm 3.00 cm +4.00 uC, and the net force F on 43 is entirely in the negative.r- direction. (a) Considering the 41 5.00 cm different possible signs of q, and there are four possible force diagrams representing the forces and F, that q, and 42 exert on 43. Sketch these four possible force config- urations, (b) Using the sketches from part (a) and the direction of F, deduce the signs of the charges q, and 22. (c) Calculate the magni- tude of 42. (d) Determine F, the magnitude of the net force on 23. 42 1 1100