1. Two uniform ladders AB and BC of equal length are hinged smoothly at B. The weight of AB is W and the weight of BC is 4W. The ladders stand on rough horizontal ground with ABC = 60. The coefficient of friction between each ladder and the ground is . A decorator of weight 7W begins to climb the ladder AB slowly. When she has climbed up of the ladder, one of the ladders slips. Which ladder slips, and what is the value of