Introduction
- Whenever we throw an object towards the sky it will fall back onto the ground.
- For Example: - A ball comes down when thrown up. Rain drops fall towards the ground; Planets revolve in an elliptical orbit around sunetc.

Planets revolving in the elliptical orbit.
Rain drops falling on the earth.
Leaves fall off the tree.
- There is a force due to which all things are attracted towards the earth. This force is known as Gravitation.
- Gravitation is the force of attractionbetween all masses in the universe, especially the force of attraction exerted by the earth on all the bodies near its surface.
- In this chapter we will take a look at gravitation force, its laws, and we will also study about the planetary motion.