- #1

nmelott

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## Homework Statement

A 500lb box is being pushed up a ramp which is sloped at 10 deg. The center of mass of the box is at the geometric center of the shown area. If the static coefficient of friction is 0.35 and the kinetic coefficient of friction is 0.28, what is the force P that will cause the box to tip? What is the force P that will cause the box to slide?

## Homework Equations

*I resolved the weight into x and y components as my online homework allows me to set the axis to whatever I want, so I set it to move 10 degrees.

Wx=Weight*sin(10)

Wy=Weight*cos(10)[/B]

ΣFx:0=P-Slipping Force-Wx

ΣFy:0=N-Wy

Slipping force= μ(kinetic)N

θ

## The Attempt at a Solution

So I solved for the force P that causes the box to slide by the sum of the forces in the x direction.

P=Slipping Force+Wx

P=μ(kinetic)N+Weight*sin(10)

P=.28*Weight*cos(10)+Weight*sin(10)

P=.28*500*cos(10)+(500*sin(10))=224.7lb

That is correct, but I keep getting the wrong answer for the force that causes the box to tip. I am using a moment equation about the right bottom corner of the box(it is being pushed from the left, top side) and setting it equal to zero. Is a moment equation the right way to go about this or am I using the wrong approach?