Ladder leaning against the wall, that we dont want to fall down

  1. problem:

    ladder is leaning against the wall.

    There is friction between ladder and wall - f1

    and there is friction between ladder and ground - f2

    what is the minimal angle between ladder and ground that ladder doesn't fall down.



    I though it's easy, but then i realized it's not only about force - it's also about "circle motion" (you know what i mean). I dont know hot to solve it.


    tell me if my description itn's clear so i'll make picture.
     
  2. jcsd
  3. tiny-tim

    tiny-tim 26,054
    Science Advisor
    Homework Helper

    Hi hellbike! :wink:

    You need to very carefully give names to the horizontal and vertical components of all the forces, and then balance the horizontal and vertical components (separately), and also take moments about some suitable point. :smile:
     
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