Gravitation is the force of attraction between any two objects with mass. This force is what causes objects to fall to the ground, keeps planets in orbit around stars, and governs the motion of galaxies in the universe.

Newton's Observation and Thought Process

1.The Falling Apple: According to popular lore, Isaac Newton started thinking about gravity when he saw an apple fall from a tree. He wondered why the apple fell straight down to the ground and did not move sideways or upward.

2.Earth's Attraction: Newton realized that the earth attracts the apple towards itself. He then pondered whether the same force that attracts the apple to the earth could also attract the moon.

3.The Moon's Orbit: Newton hypothesized that the same gravitational force that pulls the apple towards the earth also keeps the moon in orbit around the earth. The moon is continually falling towards the earth but also moving forward, creating a curved path around the earth.

4.Centripetal Force: The force that keeps an object moving in a circular path is called centripetal force. This force acts towards the centre of the circle. For the moon, the centripetal force is provided by the gravitational attraction of the earth.

Gravitational Force on Earth

1.Falling Objects: On Earth, gravity causes objects to fall towards the ground. For example, when you drop an apple, it falls because the earth's gravity pulls it downward.