This one has confused me in the past. I can work with formulas and come up with the right answer... but distance relative to what? And does it mean that if I'm accelerating in a rocket then I do more and more work with every passing second if my thrust is constant? How does that make sense? Or if you look at, say, me walking from a frame of reference that is moving backwards to my direction of motion at a million miles an hour, would you come up with me doing enormously more work than looking at it from the frame of reference of the ground, because my distance covered from the million-mile-an-hour frame of reference is so much greater? If so, what do the multiple answers mean?