Determine the strength and direction of the electric field at the position indicated by the dot in (Figure 1). Assume that x -axis is horizontal and points to the right, and y -axis points vertically upward. Figure1 of 1 A rectangle has horizontal sides of 4.0 centimeters each and vertical sides of 2.0 centimeters each. A dot is at the bottom left vertex of the rectangle. A positive charge of 10 nanocoulombs is at the bottom right vertex. Another positive charge of 10 nanocoulombs is at the top right vertex. A negative charge of negative 5.0 nanocoulombs is at the top left vertex. Part A What is the magnitude of the field? Express your answer with the appropriate units