Answer:
As the mass of the chest increases, more force is required to pull it.
Explanation:
Mass is a measure of the inertia of a body. Inertia means reluctance towards motion. A heavier object has a greater degree of inertia than a lighter object.
Hence, the student will notice that more force is required to move a heavier chest of books than a lighter one.
Therefore, as the mass of the chest increases, more force is required to pull it.