Coulomb's law for the magnitude of the force $F$ between two particles with charges $Q$ and $Q'$ separated by a distance $d$ is
$|F| = K \frac{|QQ'| }{d^2}$,
where $K = \frac{1}{4\pi \epsilon_0}$, and
$\epsilon_0 = 8.854 \times 10^{-12} C^2/(N \cdot m^2)$ is the permittivity of free space.
Consider two point charges located on the x axis: one charge, $q_1 = -19.5 nC$, is located at $x_1 = -1.690 m$; the second charge, $q_2 = 36.5 nC$, is at the origin ($x = 0$).
