Class 9 Science chapter 10, Gravitation, introduces students to the concept of gravitation and its effects on objects. The chapter covers topics such as the law of gravitation, gravitational force, weight, and the gravitation of celestial bodies. It also covers the application of these concepts in real-world scenarios, such as the motion of planets and satellites, and the tides. The chapter aims to help students understand the fundamental principles of gravitation. Andhow they can be applied to explain the behavior of objects in the world around them.

The topics that we are going to understand in this Chapter are :-

- The law of gravitation, including the formula and its derivation
- The gravitational force between two objects and its relationship to mass and distance
- The gravitation of celestial bodies, such as planets and satellites, and their orbits
- The tides and their causes
- The escape velocity and its applications
- The fundamental principles of gravitation and how it affects the motion of objects in the world around them

## Gravitation

Gravitation is the force of attraction between any two objects in the universe. It is one of the four fundamental forces of nature, along with electromagnetism, the weak nuclear force, and the strong nuclear force. The force of gravitation is proportional to the product of the masses of the two objects and inversely proportional to the square of the distance between them. This relationship is known as the law of gravitation, which was first proposed by Sir Isaac Newton in his laws of motion. The formula for the law of gravitation is:

F = G (m1 * m2) / r^2

- Where,
- F is the force of gravitation,
- G is the gravitational constant,
- m1 and m2 are the masses of the two objects, and
- r is the distance between their centers of mass.

The same formula is written in the PDF Notes of Class 9 Science Gravitation. PDF Notes are Give Above.

Gravity is the force that attracts objects towards the center of the Earth, or any other celestial body. This is why objects fall towards the ground when dropped. The force of gravity also keeps the planets in orbit around the sun and the moon in orbit around the Earth.

### Law of Universal Gravitation

Newton’s Universal Law of Gravitation, also known as the law of gravitation, is a scientific law that states that every point mass in the universe attracts every other point mass with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them. The formula for the law of gravitation is:

F = G (m1 * m2) / r^2

Where F is the force of gravitation, G is the gravitational constant, m1 and m2 are the masses of the two objects, and r is the distance between their centers of mass.

The law of gravitation was first proposed by Sir Isaac Newton in 1687 and is considered one of his laws of motion. It is a fundamental law of physics and applies to all objects in the universe, from subatomic particles to galaxies. The law can be used to calculate the gravitational force between two objects and also to explain the motion of celestial bodies such as planets and satellites.

Newton’s law of gravitation helps to explain the motion of celestial bodies in the solar system. The motion of a projectile under the influence of gravity. It also helped to explain the observed motion of the planets and the moon, which had long been a mystery.

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