Question

After a long night of cramming for a test, your college room-mate hits his head forcefully against the wall of your room in despair. According to Newton’s 3rd Law, as he exerts a force against the wall, there must be an equal and opposite force. How does that opposite force show itself in this case?

Answer 1

Answer: the wall contracts the force exerted by his head. The wall produces the opposite force which is equal to the force his head bangs the wall with.

Explanation: if his head exerts a much greater force than the wall can counteract the wall will be destroyed, if the wall exerts a much greater force than his head exerts he will be pushed far back and might even suffer a broken head.

The wall in this case provides the opposite reactive force.