Explain how from Newton.s `1^(st)` law of motion the qualitative idea of inertia and force develops.

Explanation

Newton.s first law: If a body is in a state of rest, it will remain in the state of rest and if the body is in the state of motion, it will remain moving in the same direction with the same speed unless an external force is applied on it.
(i) Qualitative idea of inertia: The `1^(st)` part of Newton.s first law of motion gives the qualitative idea of inertia. Inertia is the property of a body by virtue of which it tends to continue its state of rest or of uniform motion.
(ii) Qualitative idea of force: The `2^(nd)` part of Newton.s first law gives a qualitative idea of force. Force is the external agency which when acts on a body can move a stationary body or which can stop a moving body.