FE Review: Statics Problem 9

[@JasonSam7]

Jeff you are a great professor and when I take my first salary i've sworn to donate to you.Thank you! From Greece, mechanical engineering in Uni of Patras!

[@Sasuki774]

I love you Jeff

[@timothycai6534]

hi Jeff, quick question, when you are summing up the moments, why you multiply the weight of the ladder by 2ft instead of half of the length of the ladder? and likewise why don't you multiply the weight of the man by the full length of the ladder? Is that because the weight is always vertically downward, and you always pick the shortest distance from the line along the forces toward the center of action? (i.e. fulcrum?)

[@1234jhanson]

Because the distance should be perpendicular to the force. So it’s half the with of the base of that triangle. Hope this helps.

[@andrewnettleton411]

A moment is equal to Force times perpendicular distance! The load of the ladder is at it's center of gravity, which places it 2 ft perpendicular x distance from point B