Your empty hand is not hurt when it bangs lightly against the wall?

Question

Why is it hurt if it does so while carrying a heavy load? which of Newton's Law ismost applicable here???


Please help me. .
thanks!

Answer 1

Your hand is squeezed between the wall and the heavy object.

As for Newton, "an object in motion stays in motion unless acted on by an outside force"? (In this case, your hand being mashed between the object and the wall. It is the force your hand exerts that finally brings the object to a stop.)

The situation is essentially the same as if your hand didn't move at all but was the target of a heavy object moving through the air on its own with the same velocity.