From Paper 3: Statistics and Mechanics
1012 marks
A uniform ladder of length 6 m and mass 20 kg rests with its top against a smooth vertical wall and its foot on rough horizontal ground. The ladder makes an angle of 60° with the ground.
(a) The ladder is on the point of slipping. Find the coefficient of friction between the ladder and the ground.
(b) The ladder is moved so that the coefficient of friction is 0.4, at the same angle. A man of mass 70 kg climbs the ladder. Modelling the man as a particle, find how far up the ladder he can climb before it slips.