A ladder of mass M and length 4 m rests against a frictionless wall at an angle of 50 degrees to the horizontal. The coefficient of static friction between the ladder and the floor is 0.45. What is the maximum distance along the ladder a person of mass 13M can climb before the ladder starts to slip?
How can I do this problem ?
you could spend a few seconds with google.
Maybe you can start here. There are many other hits on the ladder problem.
rhettallain.com/2018/12/11/the-ladder-problem/