Every object in the universe attracts every other object with a force which is called the force of gravitation.
Gravitation is one of the four classes of interactions found in nature. These are
( i) the gravitational force( ii) the electromagnetic force( iii) the strong nuclear force( also called the hadronic force).( iv) the weak nuclear forces.
Although, of negligible importance in the interactions of elementary particles, gravity is of primary importance in the interactions of objects. It is gravity that holds the universe together.
Newton’ s Law of Gravitation
Gravitational force is a attractive force between two masses m1 and m2 separated by a distance r.
The gravitational force acting between two point objects is proportional to the product of their masses and inversely proportional to the square of the distance between them.
Gravitational force.
where G is universal gravitational constant.
The value of G is 6.67 X 10-11 Nm 2 kg-2 and is same throughout the universe.
The value of G is independent of the nature and size of the bodies well as the nature of the medium between them.
Dimensional formula of Gis [ M-1 L 3 T-2 ].