A cylinder rolls up an inclined plane, reaches some height, and then rolls down (without slipping throughout these motions). The directions of the frictional force acting on the cylinder are
Options

Question

A cylinder rolls up an inclined plane, reaches some height, and then rolls down (without slipping throughout these motions). The directions of the frictional force acting on the cylinder are

G1 Physics · Accepted Answer

For pure rolling on a fixed incline, friction is static and provides the torque needed for angular acceleration. For a symmetric cylinder it is up the incline both while moving up and while rolling back down. Hence B.