Roger pushes a box on a 30° incline. if he applies a force of 60 newtons parallel to the incline and displaces the box 10 meters along the incline, how much work will he do on the box?

We have to compute first its force before we can get the work done on the box.

Force = m * a
m = 60 newtons
a = cos30 (since Roger applies force parallel to the incline, we will use cosine)
F = 60 * cos30
F = 51.9615... N

Work done = F * d
F = 51.9615... N
d = 10 meters
W = 51.9615... N * 10 meters
W = 519.6152... Joules or 520 J