Question

If a man jumps out from the boat, and the boat moves backwards. Why?

Answer 1

The man jumps out from the boat, to jump out he has to push himself upward while pushing himself upward he has to exert an amount of force to lift himself up. This upward force creates an equal and opposite force in downward direction which causes the boat to move backward.

Answer 2

It can be said to be an application of Newton's third law of motion. When the man steps out of the boat,he exerts pressure on the boat which is the action.The boat then applies an equal force on the man and moves backward(reaction) to enable him to move forward.