Read the following case and answer the following questions:
For centuries, people have used flowing water to perform useful work. In a traditional watermill, water stored at a higher level flows downward and strikes a water wheel. As the water flows, its gravitational potential energy is converted into kinetic energy, causing the wheel to rotate. This rotational motion is then used to operate machines such as grinding stones for grinding grains. Thus, a watermill is a simple machine that makes work easier by using the natural energy of flowing water.
The same principle is used in modern hydroelectric power plants. Water stored behind a dam flows through pipes and rotates turbines, which are connected to generators. The generators convert the mechanical energy of the rotating turbines into electrical energy. Since flowing water is continuously renewed through the water cycle, hydroelectric power is a renewable source of energy that helps generate electricity while reducing the use of fossil fuels.
The same principle is used in modern hydroelectric power plants. Water stored behind a dam flows through pipes and rotates turbines, which are connected to generators. The generators convert the mechanical energy of the rotating turbines into electrical energy. Since flowing water is continuously renewed through the water cycle, hydroelectric power is a renewable source of energy that helps generate electricity while reducing the use of fossil fuels.
1. As water flows from the reservoir towards the water wheel, which energy transformation occurs before the wheel begins to rotate?
2. Which part of the watermill directly receives the kinetic energy of the flowing water?
3. If the water stops flowing through the watermill, what is the most likely reason the grinding stone also stops rotating?
4. A student says, "A watermill can continue rotating forever even if no more water flows because it has already started moving." Which statement best evaluates this claim?