What is more demanding to process regarding the movement/motion of an object? Physics engine or animation engine? And why?

Recently I was given the simple task to move an object in world space. I was asked to animate the movement as oppose to coding it (i.e. translate, add force, etc.). Is there real benefit to doing this in respect to optimization? How do the two different engines (physics vs. animations) differ in this goal? Which one takes the least amount of computer power? And why?