Question

rolling a drum is work against friction.why?​

Answer 1

It does rotational work. We can view this work as a medium between gravitational potential energy and rotational kinetic energy. So when it accelerates down the incline, friction force takes some of the gravitational potential energy and turns it into rotational kinetic energy for the cylinder.

Answer 2

Explanation:

Because there is no relative motion between the rolling object and the surface it rolls on, pure rolling friction generates no work. Because of relative motion, sliding friction works.

Friction keeps the wheels rolling at a faster pace. External force changes the motion of a rolling body. This can happen in a variety of ways: The external force's line of action travels via the center of mass.