Question

State Newton’s universal law of gravitation. Express it mathematically. Mention any two phenomena which were explained on the basis of this law.

Answer 1

Every object in this universe attracts every other object with a force which is directly proportional to the product of their masses and inversely proportional to the square of distance between them. This force is along the line joining the centres of the two objects.
F = G.\(\frac { Mm }{ { d }^{ 2 } } \)
Where F = Force; Mm = Product of two masses
d = Distance between the centres of two objects
G = Universal Gravitation constant = 6.67 × 10^-11 Nm² kg^-2
Phenomena which were explained on the basis of universal law of Gravitation:

• The force that binds us to the earth.
• The motion of moon around the earth.
• The motion of planets around the sun.
• The formation of tides due to the moon and the sun.