Homework Help: Help finding coefficient of friction

1. Nov 15, 2006

Soshamim

Hey, I was wondering if someone could help me with this statics problem.

The question is: "The 1600kg car is just beginning to negotiate the 16* ramp. If the car has rear-wheel drive, determine the minimum coefficient fo static friction required at B.

My FBD:

The answer I keep getting is 0.395, but the book says Us = 0.365.

I'm about to type up my work in a second

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2. Nov 15, 2006

Soshamim

$$\Sigma \vec{F}_{x} = \vec{f}_{B} - \vec{A} sin(16) = 0$$
$$\Sigma \vec{F}_{y} = \vec{B} + \vec{A} cos(16) - G = 0$$
$$\Sigma \vec{M}_{B} = -1.475*G + 2.545*\vec{A} cos(16)$$

.....From moment equation, A = 9463N
....From Fy equation, B = 6599N
....From Fx equation, Fb = 2608N

Using Fb = u*B, I get u = 0.395, which is not the correct answer. I'm not really sure what I'm doing wrong here.