# 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 a) Up the incline while ascending and down the incline while descending b) Up the incline while ascending as well as descending c) Down the incline while ascending and up the incline while descending d) Down the incline while ascending as well as descending

## Question ID - 100526 | SaraNextGen Top Answer 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 a) Up the incline while ascending and down the incline while descending b) Up the incline while ascending as well as descending c) Down the incline while ascending and up the incline while descending d) Down the incline while ascending as well as descending

Answer Key / Explanation : (b) -

(b)

When the cylinder rolls up the incline, its angular velocity  is clockwise and decreasing

This require an anticlockwise angular acceleration , which is provided by the force of friction  acting up the incline

When the cylinder rolls down the incline, its angular velocity  is anticlockwise and increasing. This requires an anticlockwise angular acceleration , which is provided by the force of friction  acting up the incline