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?

Pretty sneaky, I must say!

Work = (force) x (distance)

That formula says nothing about the directions of the force OR

the distance. As long as they're both in the same direction, they

can both be horizontal (sliding a crate on the floor), vertical (lifting

something), or on any slant in between.

Roger's force and distance are both in the same direction ... the

direction of the incline ... so

Work = (60 newtons) x (10 meters) = 600 joules.