## Gravitation – Class 11 | Chapter – 8 | Physics Short Notes Series PDF for NEET & JEE

Gravitation: Gravitation is the force that attracts two objects with mass or energy toward each other. It is one of the four fundamental forces of nature, along with electromagnetism, the strong nuclear force, and the weak nuclear force.

The theory of gravitation was first proposed by Sir Isaac Newton in the 17th century, and it states that every object in the universe attracts every other object with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

In the early 20th century, Albert Einstein developed the theory of general relativity, which replaced Newton’s theory of gravitation and provided a more accurate explanation of gravitational effects. According to general relativity, gravity arises from the curvature of spacetime caused by the presence of mass and energy.

## Newton’s Law of Gravitation

Newton’s Law of Gravitation is a fundamental law in physics that describes the gravitational force between two objects with mass. It was formulated by Sir Isaac Newton in the 17th century and is considered one of his most significant contributions to science.

The law states that every object in the universe attracts every other object with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Mathematically, this can be written as:

F = G (m1m2)/r2

where F is the gravitational force between two objects, 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 gravitational constant, denoted by G, is a fundamental constant of nature that determines the strength of the gravitational force. Its value is approximately 6.674 × 10-11 N·m2/kg2

Newton’s Law of Gravitation applies to all objects with mass, from tiny particles to celestial bodies like planets, stars, and galaxies. It explains why planets orbit the sun, why the moon orbits the Earth, and why objects fall towards the Earth’s surface.

## Formula of Gravitational Force

According to Newton’s law of gravitation, every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Mathematically it can be represented as,

F = Gm1m2/r2

Where,

• F is the Gravitational force between two objects measured in Newton (N)
• G is the Universal Gravitational Constant with a value of 6.674 × 10-11 Nm2kg-2
• mis the mass of one massive body measured in kg
• m2 is the mass of another massive body measured in kg
• r is the separation between them measured in kilometre (Km)

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