What are the differences between Coulomb force and gravitational force ?

Explanation

1) The gravitational force between two masses is always attractive but Coulomb force between two charges can be attractive or repulsive, depending on the nature of charges.
2) The value of the gravitational constant `G = 6.626 xx 10^(-11) Nm^(2) kg^(-2)`. The value of the constant k in Coulomb law is `k = 9 xx 10^(9) m^(2)C^(-2)`.
(3) The gravitational force between two masses is independent of the medium. The electrostatic force between the two charges depends on nature of the medium in which the two charges are kept at rest.
(4) The gravitational force between two point masses is the same whether two masses are at rest or in motion. If the charges are in motion, yet another force (Lorentz force) comes into play in addition to coulomb force.