The E-field at the center of 4 charges You construct a rectangle that is 6cm by 8cm, and place the following four charges at each corner: 2mC, -4mC, 2mC, -3mC. The 2mC starts at the top left corner and then each is placed around the rectangle in order in a clockwise manner. A) What is the E-field at the center of the rectangle? B) What is the Potential at the center of the rectangle? The only way i could think of to go about solving this was to separate the rectangle in to four triangles, and then solve for each of their Fnetx and Fnety to determine the Net force and direction. F= (Kq1q2)/(r^2) after finding the net force i figured i could use Fnet= qE E- being the E-field but in order to do this i guess i would have to place some sort of charge at the middle of the rectangle to solve for E. i suppose i could use an electron. Would this work? or is there a simpler way i am missing? for the next part i suppose id have to find out what U is for the system. V being potential what i need, V=Ue/q Ue=(Kq1q2)/r let me know what you think.