For here, I went for W=(40*10)*(5)*(cos60)=100J
The key just said to do 40*10*5=200J. So in what case do we use cos theta? I am assuming that they used cos(0)=1, but where is this zero degree from?
I understand that the angle should be between the F and d, but I don't think I can picture where to draw that angle. I would imagine that M is lifted up perpendicular to the dashed line, making the angle between F and D 30, but that would not lead me to the correct answer.