Help finding coefficient of friction

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SUMMARY

The discussion revolves around calculating the minimum coefficient of static friction required for a 1600kg car negotiating a 16-degree ramp. The user calculated a coefficient of friction (u) of 0.395, while the reference book states the correct value is 0.365. The user provided equations of motion, including force balance equations and moment equations, but encountered discrepancies in their calculations, particularly in the application of the static friction formula.

PREREQUISITES
  • Understanding of static friction and its role in mechanics
  • Familiarity with free body diagrams (FBD) and their application in statics
  • Knowledge of Newton's laws of motion
  • Basic trigonometry for resolving forces on inclined planes
NEXT STEPS
  • Review the principles of static friction and its calculation methods
  • Study free body diagram techniques for analyzing forces on inclined planes
  • Learn about the application of Newton's laws in static equilibrium problems
  • Explore the effects of angle and weight on frictional forces in mechanics
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Students and professionals in engineering, particularly those studying statics, mechanics, or physics, will benefit from this discussion. It is also relevant for anyone involved in automotive engineering or dynamics analysis.

Soshamim
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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:
attachment.php?attachmentid=8335&stc=1&d=1163575175.jpg


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

...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.
 

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