Why does a bicyclist pick up speed on a downhill?

A bicyclist picks up speed on a downhill due to the force of gravity. When riding downhill, gravity pulls the cyclist and the bike downwards, causing them to accelerate. The steeper the slope of the hill, the greater the force of gravity, resulting in a higher speed. Additionally, factors such as the cyclist's weight and the aerodynamics of their body and bike can also contribute to the increase in speed. However, it's important for cyclists to maintain control and practice caution while going downhill, as high speeds can increase the risk of accidents.