Gravitational constant

G is the universal gravitational constant:

$G = 6.67 \times 10^{-11} \ \mbox{N} \ \mbox{m}^2 \ \mbox{kg}^{-2} \$

It is used in Newton's formula for the gravitational force between two objects, which is:

$F = G \frac{m_1 m_2}{r^2}$

where

${F} \$ is the force between the two objects

${m_1},{m_2} \$ are the masses of each object

${r} \$ is the distance between the two objects.

g is the acceleration Earth's gravitational field exerts on objects at Earth's surface:

$g = 9.81 \ \mbox{m} \ \mbox{sec}^{-2}$