The Law Of Motion

John and James were neighbours and envy of each other. One day, John while taking a walk on his terrace saw smoke all around him. He looked down and saw that James was burning some leaves. He asked him not to do so.

At this, James replied, "What can I do in this? Smoke always goes up." Then John brought a bucket full of water and poured it over the burning leaves.

When James shouted at him, he said, "What can I do in this? Water always flows down." James had no answer to this.