NEWTON'S UNIVERSAL LAW OF GRAVITATION

NEWTON'S UNIVERSAL LAW OF GRAVITATION

Every body in the universe attracts every other body with a force  which is directly proportional to the product of their masses and versely proportional to the square of the distance between them. 

Consider two masses mand m, separated by a distance, r. According to Newton's law of gravitation the force between the two masses directly proportional to the product of masses (m, m,) and inversely pro portional to the square of the distance (r).

1.

or

m, m,

F Gm m

where G is a constant called the

gravitational constant. In S.I units, G 6.67 1o " Nm kg.

The dimensional formula of G is (M 'L'T 1.

The force on mbym can be written in vector form as

F-- Gimmr, where is the unit vector from m to m2. The negative sign of gravitational force shows that it is an attractive force. Forces on the two masses are equal and opposite.

F, =-F i.e. The force on 1" particle due to 2 particle = force on 2 particle due to 1"particle.

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