Question

State Newton's second law. Prove that Newton's first law of motion is contained in Newton's second law

Answer 1

As we know Newton’s second law of motion states that the rate of change in momentum of a body is equal to the resultant force acting on the body in the direction of the resultant force.
If the resultant force acting on a body is zero (due to the action of the balanced force), the rate of change in momentum also equals to zero, Where if the rate of the momentum of a body becomes zero it does mean that the final and initial momentums are equal to each other which is also means that the final and the initial velocities are equal, Which resembles the Newton’s law of inertia i.e., Newton’s first law of motion.( i.e., 'Any body in the universe continues in its state of rest or uniform motion in a straight line unless a resultant force acts on it
to accelerate'.