Question

a child pedals a bicycle along a road at a constant speed. why does the bicycle keep moving at a constant speed? a. the net force on the bicycle is zero. b. the force of her pedaling is stronger than inertia. c. the force of friction is larger than the force of gravity. d. the force of her pedaling is stronger than the force of friction.

Explanation:

According to Newton's first - law, an object moves at a constant speed when the net force acting on it is zero. In the case of the bicycle moving at a constant speed, the forward force from pedaling balances the backward - acting frictional force, resulting in a net force of zero. Inertia is not a force and cannot be compared in strength to the force of pedaling. The comparison between friction and gravity is not relevant to the horizontal constant - speed motion. If the force of pedaling were stronger than friction, the bicycle would accelerate.

Answer:

A. The net force on the bicycle is zero.