# Formula Newton's Law of Gravity (Potential Energy of a Mass) Gravitational energy    Distance    Mass

## Gravitational energy

Unit
Gravitational energy is the potential energy of a mass $$m_2$$ which is in the gravitational field of another mass $$m_1$$ at a distance $$r$$ from it. The gravitational energy is negative (see the minus sign in the formula) so that the mass $$m_2$$ has a smaller (more negative) potential energy when it is closer to $$m_2$$.

## Distance

Unit
Distance of mass $$m_2$$ from mass $$m_1$$. The potential energy of the mass $$m_2$$ goes from negative values to zero when the mass is further away from the mass $$m_1$$.

## Mass

Unit
The mass of the first body, e.g. the earth.

## Mass

Unit
The mass of the second body, e.g. the moon.

## Gravitational constant

Unit
Gravitational constant is a physical constant and has the value $$G = 6.674 ~\cdot~ 10^{-11} \frac{\mathrm N \, \mathrm{m}^2}{\mathrm{kg}^2}$$.