Okay this one is really starting to get on my nerves. Drawing in the attachment. Mass of ladder is 12kg. Mass of painter is 60kg. The ladder begins to slip when the person is 70percent up the ladder. The wall is frictionless. What is the coefficient of static friction between the ladderand the floor? I am unsure about where i should set the axis of torque, at the painter, the CM of the ladder or the wall?