A solid cylindrical wheel rolls without slipping at constant speed along a horizontal road
PHYSICS · Single correct · AP · Physics 1: Algebra-based · Energy and Momentum of Rotating Systems · Energy and Momentum of Rotating Systems
Problem
A solid cylindrical wheel rolls without slipping at constant speed along a horizontal road. The horizontal static friction force at the point of contact is non-zero. Which statement best explains why this friction force does not change the wheel’s kinetic energy?
(a) Static friction acts perpendicular to the motion of the wheel’s center of mass, so it can perform no work on the wheel.
(b) Any work that static friction does is exactly balanced by equal and opposite work done by the normal force, leaving the kinetic energy unchanged.
(c) The point of contact is instantaneously at rest relative to the road, so the static friction force has no displacement and therefore does no work.
(d) Static friction merely converts translational kinetic energy into rotational kinetic energy, so the wheel’s total kinetic energy is unaffected.