The fact that the angles formed by the oars with the side of the boat all stay equal is due to the parallel nature of the oars on either side of the boat. This parallelism is a direct consequence of the relative positions of the rowers and the design of the boat.
Here is a step-by-step explanation:
1. The rowers sit in a single row, with one rower on each side of the boat. Let's call the rower on the left side A1, the rower next to A1 on the left side A2, and so on. Similarly, let's call the rower on the right side B1, the rower next to B1 on the right side B2, and so on.
2. Each rower holds an oar, which is a long, flat paddle used for propelling the boat forward. The oars are positioned in such a way that they extend outwards from the boat, with the blade of each oar immersed in the water.
3. The rowers stroke in a synchronized manner, meaning they all follow the same pattern and timing when pulling their oars through the water.
4. As the rowers pull their oars towards the stern (back) of the boat, they create a force that propels the boat forward. It is important to note that the force exerted by each oar is directed perpendicular to the oar blade.
5. Since the oars on either side of the boat are parallel, the forces created by these oars are also parallel to each other.
6. According to Newton's third law, for every action, there is an equal and opposite reaction. So, the force exerted by the water on each oar in the forward direction creates a counteracting force in the opposite direction on the boat.
7. These opposing forces cancel each other out when the oars on either side of the boat remain parallel. This cancellation prevents any net rotational force on the boat and ensures the boat moves forward smoothly and efficiently.
8. To maintain the parallel nature of the oars, the rowers must adjust the angle of their oars with respect to the side of the boat. This adjustment compensates for the natural tendency of the oars to rotate due to the rowers' movements.
In summary, the parallelism of the oars on either side of the boat ensures that the angles formed by the oars with the side of the boat remain equal. This parallelism allows the rowers to generate synchronized forces that propel the boat forward efficiently.