THE GRAVITATIONAL FORCE
What is gravitational force? Mention its important properties. Give some examples of gravitational force.
Gravitational force is the force of mutual attraction between two bodies by virtue of their masses. It is a universal force. Every body attracts every other body of the universe with this force. According to Newton’s law of gravitation, the gravitational attraction between two bodies of masses m1 & m2 and separated by distance r is given by
where G is the universal gravitational constant which is equal to 6.67 * 10^ -11 Nm^2/Kg^2.
Important properties of gravitational force:
- It is a universal attractive force.
- It is directly proportional to the product of the masses of the two bodies.
- It obeys inverse square law.
- It is a long range force and does not need any intervening medium for its operation.
- Gravitational force between two bodies does not depend upon the presence of other bodies.
- It is the weakest force known in nature.
- It is a central force (i.e., it acts along the line joining the centres of the two bodies).
- It is a conservative force (i.e., work done in moving a body against the gravitational force is path independent).
- Gravitational- force between two bodies is thought to be caused by ah exchange of a particle called graviton.
Examples of gravitational force:
‘ 1. All bodies fall because of the gravitational force of attraction exerted on them by the earth.