Coulombs law describe the force of electric interaction between two stationary charged particles. It can be formulated as
^formula
Coulombs law is an inverse-square law, meaning that the force decreases with the square of the distance between the two particles. This means that the force becomes weaker as the particles are separated, and strong when they are close together.
The Coulomb force is a vector quantity and has both magnitude and direction. The direction of the force is attractive if the charges are of opposite sign (ie. a proton and an electron) and repulsive if they are of the same sign (ie. two protons).
Coulombs law has a very similar form to Newton's law of universal gravitation. The key difference is that the Coulomb constant is much larger than the gravitational constant, making the electromagnetic force much stronger than the gravitational force between two objects with the same masses and charges.
Since the charges are opposite the force will be attractive making the final answer
The force is the same as the first example except now the force will be repulsive as both particles have the same charge making the final answer