Question

Prove that 1st law as well as 3rd law of motion are involved in 2nd law of
motion
​

Answer 1

Well !

the second law of motion states that the rate of change of momentum is directly proportional to the net external force acting on the body.

So,

you see if suppose that the rate of change of momentum is zero, that shows the net force on a body is zero

And, this implies that the momentum of the body is conserved

Suppose if we choose a system in which there's only one object.

So, analysing that one object shows that it's velocity will remain constant because mass remains constant and also, because force on it is zero, means acceleration will be zero for he body because the mass cannot be exact zero if it's a point mass.

All of this shows that First Law is involved in Second Law stating that until a source of acceleration to the body isn't given, the body will continue to be in it's original state of motion.

Similarly, we can prove for the other possiblity.

Now, coming to the Third Law.

This is applicable always because all the forces occur as action reaction pair.

And, also that the magnitude of each of these forces is same but acts on both the bodies differently

The direction of the force is opposite.

Thus, if one force acts on a body F

Other will be vectorally antiparallel to it and can be represented by -F.

Hope this helps you !