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Static friction and equilibrium - problem with geometry

  • Thread starter ShawnD
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  • #26
ShawnD
Science Advisor
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Thanks krab :smile:
 
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  • #27
joc
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darn, i got here too late :P i got

[tex]D/L \leq \mu\sin\theta + \cos\theta[/tex]

but i didn't go any further. should've realised that applying the cosine rule was the next logical step. oof. krab, why do you use [tex]\pm\mu[/tex] as the coefficient of [tex]B_x[/tex]? doesn't friction always act in the same direction in this particular scenario?
 
Last edited:
  • #28
Doc Al
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Originally posted by krab

[tex]\cos\phi\pm\mu\sin\phi=D/L[/tex]
Nicely done, krab!
 
  • #29
Doc Al
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Originally posted by joc
doesn't friction always act in the same direction in this particular scenario?
No, it doesn't. At one extreme it acts upward, at the other downward.
 
  • #30
joc
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ahh yes, thanks doc.
 

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