Every object in the universe attracts every other object with a force (gravitational force *F*_{G}) directed along the line through centres of the two objects that is proportional to the product of their masses and inversely proportional to the square of the distance between them.

*m*_{1} and *m*_{2} are masses of the two objects and *r* is the distance between them. *G* is universal constant of gravitation, which equals 6.67•10^{-26} N m^{2} kg^{-2}. Strictly speaking, this law applies only to objects that can be considered pointlike object. Otherwise, the force has to be found by integrating the forces between various mass elements.

It is more properly to express Newton’s gravitational law by vector equation:

in which *r*_{1} and *r*_{2} are position vectors of masses *m*_{1} and *m*_{2}.

Gravitational forces act on distance. Newton’s gravitational law is derived from Kepler’s law for planetary motion, using a physical assumption considering Sun as the centre and the source of gravitational force.

Additionally, every object moves in the direction of the force acting on it, with acceleration that is inversely proportional to the mass of object. For bodies on the surface of Earth, the distance *r* in gravitational law formula is practically equal to the Earth radius, *R*_{E}. If the mass of the body on Earth surface is *m* and the mass of earth is *M*_{E}, the gravitational force acting on that body can be expressed as:

where *g* is gravitational acceleration which is, although dependent on geographical latitude, usually considered as constant equal to 9.81 m s^{-2}.

Generalic, Eni. "Newton’s gravitational law." *Croatian-English Chemistry Dictionary & Glossary*. 20 Oct. 2018. KTF-Split. {Date of access}. <https://glossary.periodni.com>.

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