What determines gravitational pull?

Gravitational pull, otherwise known as the force of gravity, acts between all objects due to their mass. Around any individual mass there exists a gravitational field that will cause any other mass placed within it to be attracted to the original mass. The gravitational field strength is represented by the symbol $g$ and has units of N kg$^{-1}$.

The gravitational pull on an object depends on its mass m and the strength of the gravitational field that it is in. The formula for the gravitational force $F_g$ is

$\hspace{3em} F_g = mg$

The gravitational pull between two masses can also be found using Newton’s Universal Law of Gravitation. This law shows that the gravitational force between two objects is directly proportional to the product of their masses and inversely proportional to their separation distance.

$\hspace{3em} F_g = G\dfrac{m_1m_2}{r^2}$

Where:

$\hspace{2em}F_g$ is the force of gravity in units of N
$\hspace{2em}G$ is the gravitational constant 6.67 x 10$^{-11}$ N m$^2$ kg$^{-1}$
$\hspace{2em}m_1$ and $m_2$ are the masses of the two objects in units of kg
$\hspace{2em}r$ is the separation of their centres of mass in units of m