Question

Why does a boat move forward into the water when the boatman presses one end of the pole against the ground?

Answer 1

1. The boatman applies a force pushing the ground backward (the action).
2. The ground exerts an equal force along the pole in the opposite direction (this is the reaction).
3. The horizontal component of this reaction is a force that makes the boat move forward into the water.
4. A boatman wanting to take his boat into the water (away from the bank of the river), sits in the boat and pushes the river bank with a pole.
5. Thus, the force he exerts on the bank of the river is the action. Due to Newton's third law of motion, the bank pushes the boat in the opposite direction into the water due to reaction.