Given that,
Actual work done W=300J
Mass of block m=2kg
Inclined plan of height h=10m
We know that,
Net work done sliding a block up to a height h on inclined plane = work done against gravitational force +work done against frictional force
W=Wg+Wf
300−mgh=Wf
Wf=300−2×10×10
Wf=100J
Hence, the work done against friction 100 J