## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (3rd Edition)

The force on the 1.0 nC charge is $1.8\times 10^{-4}~N$ directed to the right.
By symmetry, the vertical component of each force on the 1.0 nC charge cancels out. The net force on the 1.0 nC charge is the sum of the horizontal component of each force. The horizontal component of each force on the 1.0 nC charge is directed to the right. $F = 2\times \frac{(k)(1.0~nC)(2.0~nC)}{r^2}~cos(60^{\circ})$ $F = 2\times \frac{(9.0\times 10^9~N~m^2/C^2)(1.0\times 10^{-9}~C)(2.0\times 10^{-9}~C)}{(0.010~m)^2}~cos(60^{\circ})$ $F = 1.8\times 10^{-4}~N$ The force on the 1.0 nC charge is $1.8\times 10^{-4}~N$ directed to the right.