Optimal force angle for moving box with friction · CAP 2003 #12
Physics · mechanics
Problem
You want to apply a force on a box so that it moves with constant speed across a horizontal floor. The coefficient of kinetic friction between the box and the floor is μk. Of the four following cases, the force you apply on the box will be smallest when you
(a) push on it with a force applied at an angle 0<θ<90° downward from the horizontal;
(b) pull on it with a force applied at the same angle θ as in (a), upward from the horizontal;
(c) do either (a) or (b) since the applied force is the same;
(d) push or pull with a force applied horizontally.