Question

Why is the foots o a man injured when he hits a stone

Answer 1

This can be understood by the Newton's a third law of motion which states that every action has an equal and opposite reaction.

When a person hits the stone , he gives an impulsive force to the stone, Also the stone gives him an impulsive reaction to the foot of the person. Due to this impulsive reaction man foot got injured.

Hope you get your answer.