1. Your empty hand is not hurt when it bangs lightly against a wall. Why is it hurt if it is carrying a heavy load when it bangs against the wall? Which of Newton’s laws is most applicable here? 2. As...

1. Your empty hand is not hurt when it bangs lightly against a wall. Why is it hurt if it is carrying a heavy load when it bangs against the wall? Which of Newton’s laws is most applicable here?

2. As you stand on a floor, does the floor exert an upward force against your feet? How much force does it exert? Why aren’t you moved upward by this force?