Newton observed an apple falling from a tree, which led him to discover his law of universal gravitation. 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. Specifically, the gravitational force between two objects equals G*(m1*m2)/r^2, where G is the gravitational constant, m1 and m2 are the object masses, and r is the distance between their centers. This explained gravity and allowed prediction of orbital motion.

1. Newton's law of Gravitation
 The idea of gravity was Introduced by Sir Isaac Newton
in the late 1600’s
 He was a scientist who combine ideas to explain how
the universe operates.
How He Discovered it…?
 Newton’s law of Gravitation was discovered
while he watched an apple fall from a tree.
 The force that pulled the apple to the ground
was the same with which apple attracted earth.

2. Gravitational Force
Gravitation force depends on two things:
 The mass of the two objects.
 The distance between the two objects.

3. Newton's law of Gravitation
Gravitational force is directly proportional to the product of masses.
Gravitational force increases as mass Increases.

4. Gravitational force is inversely proportional to
the square of distance between the masses.
Gravitational force decreases as distance
increases.

5. Newton's law of gravitation states that a particle attracts every other
particle in the universe with a force which is directly proportional to the
product of their masses and inversely proportional to .the square of the
distance between their centers.
The equation for universal gravitation thus takes the form:
where F is the gravitational force acting between two
objects, m1 and m2 are the masses of the objects, r is the distance between
the centers of their masses, and G is the gravitational constant.
This is Law of Universal Gravitation