# Gravitation and Newton’s law of gravitation

**Definition of gravitation:** Gravitation is the force of attraction between any two bodies of the universe. It It was discovered by Great scientist Newton in the year 1665 (as most of us know when he saw an apple falling down the tree)

Gravitational force is the weakest force among the four basic forces of nature.

**Newton’s law of gravitation:**

This law states that everybody in this universe attracts everybody with a force and this force is directly proportional to the product of the masses of the bodies and is inversely proportional to the square of the distance between them.

**Also read:** Gravitational force and its properties

**Derivation or relation of Newton’s law of gravitation:**

Consider two bodies A and B of masses m1 and m2. Suppose r is the distance between their centers and F be the force of attraction between them, then according to the above mentioned statement of Newton’s law

A—————————————————–B

r

F α m1m2

F α 1/r^{2}

Thus by combing the above two

F α (m1m2)/r^{2}

Or F = G (m1m2)/r^{2 }(1)

Where G is a constant of proportionality known as Universal Gravitation constant.

**Definition of Universal Gravitation constant (G):**

Suppose m1 = m2 = 1

And r =1

Then equation (1) becomes

F = G

Thus Universal Gravitation constant (G) is defined as the force of attraction acting between two bodies each of unit mass and whose centers are placed unit distance apart.

This is the concept of gravitation, Newton’s law of gravitation and about the Universal Gravitation constant.

**Brain Teaser:**

- Gravitational force is the weakest force. Please tell which is the strongest force among the four fundamental forces? Write your answer in comment section

NUCLEAR