Final answer:
The statement given is describing Newton's Second Law of Motion, which states that the force exerted on an object is equal to the mass of the object multiplied by the acceleration. Thus, a box with more mass (due to the added books) requires more force to move.
Step-by-step explanation:
The statement given is describing Newton's Second Law of Motion. This law states that the force exerted on an object is equal to the mass of the object multiplied by the acceleration of the object, often written as F=ma. When you add books to the box, you're increasing the mass of the box. Thus, according to Newton's Second Law of Motion, a larger force is required to move it.
In simple terms, it means that heavier objects require more force to move than lighter objects, if all other conditions are constant. Consequently, the box with books in it (which weighs more, i.e., has more mass) requires more force to push than an empty box.
Learn more about Newton's Second Law of Motion