Introduction of gravitation

A force is needed is needed to change the speed or the direction of motion of an object. We always observe that an object dropped from a height falls towards the earth. We know that all the planets go around the Sun. The moon goes around the earth. In all these cases, there must be some force acting on the objects, the planets and on the moon. Isaac Newton could grasp that the same force is called the gravitational force.

A stone dropped from a height falls towards the earth because the earth exerts a force of attraction (called gravity) on the stone and pulls it down. The earth attracts (or pulls) all the objects towards its centre. The force with which the earth pulls the objects towards it is called the gravitational force of the earth or gravity (of earth).

The gravitational force of the earth (or gravity of earth) is responsible for holding the atmosphere above the earth; for the rain falling to the earth; and for the flow of water in the rivers. It is also the gravitational force of earth (or gravity of earth) which keeps us firmly on the ground.

Every Objects in the Universe Attracts Every Other Object

According to the Newton, every object in this universe attracts every other object with a certain force. The force with which two objects attract each other is called gravitational force (or gravity).

If the masses of the objects (or bodies) are small, then the gravitational force between them is very small (which can not be detected easily).

If the object having very large mass, then the gravitational force becomes very large (and its effect can be seen easily).

The ‘gravitational force’ or ‘gravity’ is always a force of attraction between two objects (or two bodies).