How is a river’s potential energy changed into kinetic energy?
The river deposits sediment.
Gravity causes the river to flow.
The river stops moving.
It can’t change into kinetic energy.
The correct answer is: Gravity causes the river to flow.
To understand how a river's potential energy is changed into kinetic energy, it's important to know the concepts of potential energy and kinetic energy. Potential energy refers to the energy an object possesses due to its position or condition. In this case, the river's potential energy refers to the energy it has due to its elevated position, such as being on a higher elevation compared to its destination.
Kinetic energy, on the other hand, refers to the energy possessed by an object in motion. When the river starts flowing, its potential energy is converted into kinetic energy as it moves downstream. This conversion happens because of the force of gravity acting on the water.
Gravity pulls the river downhill, causing it to flow and gain kinetic energy. As the river descends, the potential energy it had due to its elevation is converted into the energy of its motion, which is kinetic energy.
Therefore, the correct answer is that gravity causes the river to flow, converting its potential energy into kinetic energy.