The friction force is trying to rotate it away from the drum.

And thanks to the friction force, the road doest slide.

The friction force depends on how the ground is moving.

Less dependence on the friction force, hence environment, is a possible outcome of arm swing.

It is possible to have large friction forces in the absence of a force pushing the two surfaces together.

Regarding the sliding case, the friction force is given.

Oil can make further improvement by reducing the friction force and the rate of material wearing away.

Surprisingly, the friction force does not depend on the surface area of common contact.

As stated earlier, the friction force acts in a direction opposite the motion of the block.

Anything that moves through the air produces drag due to friction forces.