2.6 Gravitational Force

What is Gravity?

Gravitational force is one of the four fundamental forces of nature. It is the attractive force between any two objects that have mass. Newton’s Law of Universal Gravitation defines this relationship with the following equation:

${F_g = G \frac{M m}{r^2}}$

${F_g}$ is the gravitational force between two objects

${G}$ is the universal gravitational constant (${6.67 \times 10^{-11}, N·m^2/kg^2}$)

${M}$ and ${m}$ are the masses of the two objects

${r}$ is the distance between their centers of mass

This equation shows that the gravitational force increases with mass and decreases with the square of the distance between the objects. The force acts along the line joining the centers of the two masses.