Question

A cyclist is riding his bike at a constant speed of S m/s, and experiences a frictional force between the bike and sidewalk of 100 N. The cyclist then changes his speed to 10 m/s What effect does this increase in speed have on the frictional force between the bike and sidewalk?

A) the frictional force doubles because when speed increases frictional force also increases
B) the frictional force becomes half of what it was because when speed increases frictional force decreases
C) the frictional force increases but does not double because although friction increases with the increasing speed it does not increase as fast
D) the frictional force between the bike and sidewalk stays the same because speed does not affect frictional force

Answer 1

Answer:

D) the frictional force between the bike and sidewalk stays the same because speed does not affect frictional force

Explanation:

Friction force is equal to normal force times the coefficient of friction.  Since neither of those changes as speed increases, then the friction force stays the same.