Question

Why does a bicycle begin to slow down when you stop pedalling?

Answer 1

When you stop pedalling a bicycle, the applied forward force becomes zero.

Consequently, two major opposing external forces act on it to slow it down:

• Force of Friction: The frictional force between the bicycle’s tyres and the road acts in the direction opposite to the motion.
• Air Resistance: Air drag continuously opposes the forward movement of the bicycle.

Since there is no longer any pedalling force to overcome these resisting forces, they create an unbalanced retarding force, causing the bicycle to decelerate and gradually come to rest.