Two crates are stacked on top of each other on a horizontal floor, crate #1 is on the bottom and crate # 2 is on the top. Both crates have the same mass.
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Explanation
Question
Two crates are stacked on top of each other on a horizontal floor, crate #1 is on the bottom and crate # 2 is on the top. Both crates have the same mass.
Compared to the strength of the force necessary to push only Crate at a constant speed across the floor, the strength of the force necessary to push the stack at the same constant speed across the floor is greater because
(A) the normal force on the Crate is greater
(B) the coefficient of kinetic friction between the Crate and the floor is greater
(C) the coefficient of static friction between the Crate and the floor is greater
(D) the weight of the Crate is greater
