Question 5
Which statement correctly describes the action and the reaction when a boat is rowed?
The right answer is the one marked above.
The oar pushes the water backwards; the water pushes the oar forwards. It is that reaction which drives the boat forwards.
The pattern is always the same: to go forwards, something must be pushed backwards. In swimming the hands push water backwards; in walking the foot pushes the ground backwards.
Note that an action is always applied to another object. The oar does not push the boat — the oar and the boat are parts of the same system.