If a girl is standing still and holding a box, is she doing any work? Why or why not?

I beleive she isnt doing any work due to holding the box motionless, you must be exerting a force in the direction of the box motion. If she is just standing there holding the box their isn't no work becuase no distance has been covered. work = force = distance.

W = F * d, and since d=0, therefore W=0.

(If you want to be mathematical about it.)