what does it means by work done against friction?

Question

this is a physics question

Answer 1

It means that you are applying some force to an object and moving it through a distance (hence you're doing "work" on it), but there is a force of friction on the object which pushes in the opposite direction from the motion (hence you're working "against" the friction).

An example is: you're sliding a box along the ground. You're applying a force of (say) 10 lbs on the box in an eastward direction, and you move it 6 feet, so you've done 10•6 = 60 ft-lbs of work on the box. But friction from the ground is pushing westward on the box at the same time that you're pushing eastward. So you have done work against friction.

Answer 2

literally working against the grain, of any sort
Regards
Ryan Dior