One sunny afternoon, Newton went to the suburbs to play. Sitting on the bench, reading the newspaper. Just then, a ripe apple fell from the tree and hit Newton right on the head.

He wants to know why the apple didn't run, but fell. He asked his mother, who didn't know how to answer. So Newton took this problem to study. Newton thought that some force of the earth might have attracted the apple to fall, and finally he discovered gravity. Then Newton's physical gravity.