A long ladder rests on the ground and against a frictionless roller at the top of a wall of height h=12.0m. The mass of theladder is 50.0kg, its center of mass is one third of the way up theladder, and its length is 18.0 m. A firefighter of mass M =78.0 kgis at the point half way up the ladder. What is the coefficient of static friction if the angle θ=68? is the angle just beforethe ladder starts sliding?