Which of the following is an example of gravitational potential energy?

Water that is behind a dam

The correct answer is option 3. Water that is behind a dam.

Gravitational potential energy (GPE) is energy stored in an object due to its position relative to the Earth's surface and the gravitational field strength. When an object is raised to a certain height above the ground, it gains gravitational potential energy because it has the potential to fall and accelerate towards the ground due to gravity. The amount of gravitational potential energy an object possesses depends on its mass, the height it is lifted, and the strength of the gravitational field.

In the case of water behind a dam, it is held at an elevated position compared to the ground level below the dam. The water's height above the ground determines its gravitational potential energy. As the water is held back by the dam, it has the potential to flow downward due to gravity. When the water is released from the dam and allowed to flow downhill, its gravitational potential energy is converted into kinetic energy as it accelerates downward.

The conversion of gravitational potential energy to kinetic energy can be harnessed for various purposes, such as generating electricity through hydroelectric power. Turbines are placed in the path of flowing water, and as the water falls from a higher elevation to a lower elevation, it spins the turbines, which then generate electricity.

In summary, water held behind a dam possesses gravitational potential energy due to its elevated position relative to the ground level below the dam. This potential energy can be converted into kinetic energy and harnessed for practical applications such as hydroelectric power generation.