problem: ladder is leaning against the wall. There is friction between ladder and wall - f1 and there is friction between ladder and ground - f2 what is the minimal angle between ladder and ground that ladder doesn't fall down. I though it's easy, but then i realized it's not only about force - it's also about "circle motion" (you know what i mean). I dont know hot to solve it. tell me if my description itn's clear so i'll make picture.