Question

define Newton third law and second law prove that f=m×a​

Answer 1

For every action, there is an equal and opposite reaction.

The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. Forces always come in pairs - equal and opposite action-reaction force pairs.

Answer 2

according to Newton's second law

dp/ dt=F

now we know that p=mv

so

f=m.dv/ dt^2

now dv/ dt^2=a (acceleration)

so

f=m*a

Newton's third law prove that every action has equal and opposite reaction