Question

A sailor jumps out from a small boat to the shore (Fig.). As the sailor jumps forward, will the boat move? If yes, in which direction and why.

Answer 1

Yes, the boat will move, but it will move in the backward direction, opposite to the direction in which the sailor jumps toward the shore.

This is explained by Newton’s Third Law of Motion. When the sailor jumps forward, he pushes the boat backwards with his feet. At the same time, the boat exerts an equal and opposite force on the sailor, pushing him forward. As a result of this backward reaction force, the boat moves in the opposite direction, i.e., backward.