Carla demonstrates newton's first law of motion by slowly pushing a book across a table. The book moves at a constant rate of speed so long as she is pushing it. Which of the following is NOT true?
The forces acting on the book are all balanced.
There is an unbalanced force on the book, acting in the direction of motion.
Her push balances the force of friction.
The upward force exerted by the table balances the book's weight.