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## Homework Statement

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

*u*. 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<X<90 downward from the horizontal;

b) pull on it with a force applied at the same angle X as in (a), upward from the horizontal;

c)do either (a) or (b) since the applied force is the same;

d)pull or push with a force applied horizontally

## Homework Equations

Ff=Fa, to keep at a constant speed

## The Attempt at a Solution

The correct answer is b but I have no idea why.

I chose c as my answer seeing that a and b would both result in the same thing, only that the weight of the box would concentrate in the front in situation (a) and that the weight would concentrate in the back in situation (b). I felt that this difference would not change the amount of force needed. Are there any other factors I have not considered? Thanks