weight of ladder = w
assume no friction between wall and ladder so
Force down on ground = w = force upon ladder from ground
now there is a horizontal force from the wall on the top of the ladder, call it F
ladder weight w down at center of ladder
take moments about ladder at ground
F * 5/2 = W (2.4/2)
so
F = (2.4 /5) W = 0.48 W
lo and behold, that F is balanced by the friction force at the base of the ladder
so mu = 0.48
A ladder leans against a wall 5 meters above the ground so a homeowner can clear his gutters of leaves from last fall. The bottom of the ladder just begins to slip when it is 2.4 meters from the wall. What is the coefficient of static friction between the bottom of the ladder and the ground?
1 answer