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Homework Statement
A uniform ladder 5 m long (and 12 kg) is leaning against the wall. The height from the ground to the point at which the ladder touches the wall is 4 m. The wall is frictionless but the ground is not. A painter (55kg) climbs 70% of the way up the ladder when it begins to slip. What is the minimum coefficient of friction?
Homework Equations
T=-T
T=F dcos@
F friction = F normal * Mu (coefficient)
The Attempt at a Solution
I figured all of the dimension and distances of the triangle. It turns out that the painter traveled 3.5 m along the ladder and is 2.8 m off the ground. The center of mass (when extended to the floor) is 2.1 m away from the point the ladder touches the ground. There is a force coming from the ground Fg which I broke into components Fy and Fx. I know Fx = Fw and that mg + M(painter)g + Fy = 0. I'm having difficulty in determining which of the forces from the ground is the friction force and the normal force. Would Fy be the normal force and Fg the frictional force?