Which of these correctly describes the work done on a book when a person lifts it vertically, at a constant speed? A. Negative work was done on the book because the book was displaced in the direction opposite to which the force was applied.
B. Work was done on the book because the book displaced in the direction a force was applied.
C. Work was not done on the book because it moved at constant velocity and so there was no net force acting on the book.
D. Work was not done on the book because it exerted as much force on the person lifting the book as the person exerted on it.