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

Options

A. up the incline while ascending as well as descending
B. up the incline 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 descinding

Answer

B