AAI ATC Junior Executive 27 Jul 2022 Shift 1 Paper

A charge Q₁ of 3.0 μC is placed at point (36 cm, 0) and another charge Q₂ of 9.0 μC is placed at a point (0, -27 cm).
Let i and j be the unit vectors in x- and y- directions, respectively. The force exerted by Q₂ on Q₁ is: