The weight of the man is 180 lb. As he climbs the ladder, he stops at the position shown on the figure.The friction at A is u, = 0.4. The

weight of the ladder is neglected. (i) 10 points: Draw the free body diagram. It is assumed that the contact at B is smooth. (ii) 10 points: State the equation of equilibrium relative to 0. (iii) 10 points: Draw the moment equation in function of 0and determine the angle before the ladder slip. You may use a spreadsheet software. (iv) 10 points: Suppose that the man wants to go all the way up, namely the point G is at B, and the angle of the ladder is 0 = 60°, what should be the friction coefficient before slipping?