Question

Can the work done by kinetic friction forces be positive?

Answer 1

It depends what you mean by "kinetic friction".

If you consider as "kinetic friction" the pair of action-reaction friction forces, then the sum of their works or powers will always be negative, in any frame of reference.

If you consider only the single friction force acting as an external force on you system, then its power will be negative in the frame of reference defined by the base of the motion.

So, if the base is fixed in you frame of reference, then this friction force will work negatively.

So the only friction force that can do positive work is the one exerted by a moving base acting on your system. Typically, if you pull a sheet of paper with a box resting on it. Whatever the accelerating resulting in static or kinetic friction, the work of the friction force acted by the sheet on the box will be positive.