The definition of work states that the object must move in the same direction as the force. W=Fd. I am contemplating whether or not the earth is doing "work" on the moon. My answer would be no, because no energy is being transferred, and the moon stays at around the same height (we are assuming a perfectly circular orbit). But... then I think that the moon IS constantly falling towards the earth, but it keeps missing it due to it's velocity... I am confused. lol, thanks.