Every particle in this universe attracts every other particle with a force that is proportional to the product of these masses and inversely proportional to the square of the distance between them.NEWTON’S LAW OF UNIVERSAL GRAVITATIONThus, F = Gmm/r², where and are the gravitational masses of the particles, r is the separation between them and G is Universal Gravitational Constant. Magnitude (and unit) of G: 6.67×10 ˉ¹¹ Newton. m²/kg². Dimension of G: Mˉ¹L³Tˉ²

Points to be noted about Gravitational Force:

Gravitational force is always attractive in nature and directed along the line joining the particles.

It holds good for long distances like inter-planetary distances and also for short distances like inter-atomic distances.

It is a conservative force .Therefore, the work done by the gravitational force on a particle does not depend on the path described by the particle. It depends upon the initial and final position of the particle.