Final answer:
As a cyclist ascends a hill, their potential energy increases and kinetic energy decreases. Upon descending, their potential energy converts to kinetic energy, displaying the conservation of energy. The peak of the hill represents the point of highest potential energy.
Step-by-step explanation:
When we talk about cycling up and down hills, we're discussing the transformation between kinetic energy (KE) and potential energy (PE). As a cyclist goes up a hill, they are working against gravity which increases their PE; as they go down, gravity does work on them, increasing their KE. On top of the hill, the cyclist has the highest amount of PE because they are at the greatest height relative to the surrounding area. During the process where the transformation of energy occurs, due to factors like air resistance and friction, some energy is usually converted into thermal energy.
Consider a scenario similar to a roller coaster. Work is done on the roller coaster (or cyclist) to get it to the top; at this point it has maximum gravitational potential energy and minimum KE. As the coaster descends, its PE is converted to KE, and it speeds up. As it rises again, KE is transformed back into PE, and the speed decreases. If we apply this analogy to a cyclist, while going up the hill, their PE increases (work done against gravity) and KE decreases (due to climbing). Conversely, as they descend, their PE is converted to KE, increasing their speed. These energy transformations are a fundamental part of classical mechanics, demonstrating the conservation of energy principle.