Two point charges are placed on the $-$axis: one at the origin and the other at $=0\mathrm{.}600.$ Find:

$($a$)$ the magnitude and direction of the Coulomb force between the two charges. $($b$)$ the electric potential energy of the system consisting of the two charges.

$($c$)$ the magnitude and direction of the electric field at a point $1\mathrm{.}0$ m to the left of the origin.

$($d$)$ the electric potential at the same point. What is the physical meaning of its value?