C) a bicyclist riding up a steep hill
The metaphor for a system with rising gravitational potential energy is "a bicyclist riding up a steep hill." Let's get into greater detail:
A cyclist faces resistance from gravity as they ride up a steep slope. The cyclist's elevation, or height above the ground, rises as they cycle and climb uphill. Gravity is pulling the cyclist down the hill by exerting downward force. The cyclist must apply force to the pedals in order to move forward and overcome the pull of gravity. In order to do this, the bicyclist must transform chemical energy from their body into mechanical energy. The distance of the cyclist from the centre of the Earth grows as they ride up the hill. The height and mass of an object affect its gravitational potential energy. In this scenario, as the bicyclist's height rises, their gravitational potential energy also rises.
Due to the higher elevation, the energy input from the biker is stored as increased potential energy. When the bicycle descends the hill or does work, this potential energy can be transformed back into kinetic energy or other types of energy.
