Question

To displace a boat ahead in water, the boatman has to push the water backwards by his oar. Explain.

Answer 1

Hint The three physical laws that are devised or framed by Newton known as the Newton's laws of motion together, assigned the basics for traditional mechanics. It describes the relationship between a body and the forces acting upon it, and the motion that are in response to those forces.

Complete step by step solution
In accordance with Newton's third law of motion, every action has the same and contrasting reaction. That, if the boatman desires to displace the boat forward in water, the boatman has to push the water in a backwards direction. By propelling the water, the boatman exerted a force on the water in a backward direction. Which in turn, the water applies the same amount of force that was applied in the water in forward direction, which results in moving the boat forward.
Therefore, to displace a boat forward, the boatman has to propel (that is action) the water in backwards direction with his oar. Which in this response, the water delivers a same and a contrasting force (that is reaction) in the forward direction on the boat due to which the boat displaces forward. In the same manner to displace a boat backward, the boatman has to propel (that is action) the water in forward direction with his oar. In this response, the water delivers a same and a contrasting force (that is reaction) in the backward direction on the boat due to which the boat displaces backward.

Note The first law of motion explains the force subjectively, the second law of motion explains a subjective measure of the force, and the third law of motion explains that a single secluded force does not exist.