Question

(a) Explain Newton's first law of motion with an example.
(b) $F=\frac{G{m}_1{m}_2}{d^2}$ is the mathematical form of Newton's law of gravitation.
Give the statement of Newton's law of gravitation.

Answer 1

(a) Newton's first law of motion states that:

An object remains in the state of rest or of uniform motion in a straight line unless compelled to change that state by an applied unbalanced force.

All objects resist a change in their state of motion. The tendency of undisturbed objects to stay at rest or to keep moving with the same velocity is called inertia. This is why, the first law of motion is also known as the law of inertia.

Eg.: A ball at rest on the ground continues to be at rest unless someone kicks it or any external force acts on it.

(b) Every object in the 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 the distance between them.