posted by roshna .
A neighbor pushes a lawn mower on a lawn that is level with a force of 230 Newtons. If 45% of this force is directed downward, how much work is done by the neighbor in pushing the mower 8 meters?
The force directed horizontally is not the remaining 55%, it is
sqrt[1 - (0.45)^2] = 89.3%,
which amounts to 205.4 Newtons.
Multiply that by 8 meters for the work done.
Note that Fx^2 + Fy^2 = Ftotal^2