Unformatted text preview: a) How far can the person climb up the ladder before it begins to slip? We have F x : F R = N W , where F R is the force of friction and N W is the normal force exerted by the wall, and F y : N G = W P + W L , where N G is the normal force exerted by the ground, W P is the weight of the person and W L is the weight of the ladder. We can put these together: F R = μN G = μ ( W P + W L ) = N W . Now we calculate torque about the base of the ladder. τ : L N W sin( θ ) − L/ 2 W L cos( θ ) − x W P cos( θ ) = 0 . Thus: x = Lμ ( W P + W L ) sin( θ ) − L/ 2 W L cos( θ ) W P cos( θ ) = 2 . 51 m ....
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 Fall '06
 Buchler
 Physics, Acceleration, Force, Friction, Gravity, Normal Force, WL cos, WP cos

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