Question

Derive first law of Newton from second law.

Answer 1

Proof of Newton’s First Law of Motion from Second Law

First law states that if external force F = 0, then a moving body keeps moving with the same velocity, or a body at rest continues to be at rest.

(b) A body is at rest i.e., u = 0. 

Therefore, from above u = v = 0 

So, the body will continue to be at rest.