Frank needs to move a box by sliding it across the floor. Which two factors will most strongly affect how hard Frank needs to push the box. Choose your answer from: [1]. The density of the box material and the hardness of the floor. [2]. The thickness of the box material and the hardness of the floor. [3]. The total mass of the box and the friction between the box and the floor. [4]. The total height of the box and the distance between his hands and the floor.
Answer: