If a 12-N force is applied continuously through a distance 
of 12m, then the amount of work done is
           (force) x (distance) = (12 N) x (12 m)  =  144 joules.
Power = (work done) / (time to do the work)
            =     (144 joules) / (3 sec) =  48 joules/sec = 48 watts.  
We don't care what purpose the force was used for, 
or how much friction was involved.