Question

Which law of Newton is called the law of equilibrium?
A. Newton’s first law of motion
B. Newton’s second law of motion
C. Newton’s third law of motion
D. Newton’s law of gravitation

Answer 1

Hint:Newton’s laws of motion are used to describe how the body or an object moves from one place to another and gives the definition of force and why does a body do motion while Newton’s law of gravitation states why objects with masses are attracted to each other and hence move towards each other.

Complete answer:
 Newton’s first law states that every object at rest tends to remain at rest and every object moving with uniform velocity tends to continue its motion i.e. tends to maintain its state of "Equilibrium" until and unless an external force upon it.

Newton’s second law states that the force exerted upon a body is dependent upon the mass of the body and the acceleration of the body.Newton’s third law of motion states that the forces in the universe balances each other out, that is every action has equal and opposite reaction.

Newton’s law of gravitation states that, “Every particle in the universe attracts every other particle in the universe through a force which is directly proportional to the product of the two masses, and inversely proportional to the square of distance between them.” The direction of this force is about the line joining them. This force of attraction of a particle towards another particle is called the gravitational force.

Hence option A is the correct answer.

Note: Newton’s law of gravitation explains why the planets move around the Sun and why their motion is elliptical. Newton’s gravitational law also explains why tides are produced in seas and oceans which are due to the moon and also why the moon revolves around the earth. Newton’s law of equilibrium shows why there is motion of a body.