3) (10 Points) Four point charges are held fixed in space on the corners of a rectangle with a length of 20 [cm] (in the horizontal direction) and a width of 10 [cm] (in the vertical direction). Starting with the top left corner and going clockwise, the charges are q, =+10 [nC] , q2=-10[nC] , q;=-5[nC] , and 94=+8[nC] . a) Find the magnitude and direction of the electric force on charge 94 b) Find the magnitude and direction of the electric field at the midpoint between 9; and 94 c) Find the magnitude and direction of the electric field at the center of the rectangle