Anonymous
Anonymous asked in Science & MathematicsPhysics · 7 years ago

If a curve with a radius of 79m is perfectly banked for a car traveling 71 km/h , what must be the...?

If a curve with a radius of 79m is perfectly banked for a car traveling 71 km/h , what must be the coefficient of static friction for a car not to skid when traveling at 89km/h?

Update:

Yes, It is asking for the coefficient of static friction

3 Answers

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  • Steve
    Lv 7
    7 years ago
    Favorite Answer

    Bank angle Θ = arctan[v²/(Rg)] = 26.675°

    For 89 k/h,

    µ = [V² - RgtanΘ]/[Rg + V²tanΘ] = 0.205

    Source(s): Free body diagram My 'cheat sheet' of physics formulae
  • Anonymous
    7 years ago

    trick question? does it specifically say static friction?

    mu N is friction force, mu N r is frictional torque.

    so if friction is = to the force outward, then mu N r = m a r

  • 7 years ago

    It is perfectly banked at v=71km/h=19.72m/s..R=79m

    Fcf=f....Fcf=Fcp=mv2/R....slope "α"

    f=N*µ...N=mg cosα *µ.......µ.=tanα =senα /cosα

    m*v2/R=mg*cosα *µ...v2/R=g.senα ...sen α =v2/Rg = 0.5

    then α =30° ...µ=tan α =0.5773

    Now at v=89km/h=24.72 m/s

    the coefficient of static friction is:

    mv2/R =mg*cosα*µ .......µ.st=v2/(Rg* cos30°)=0.91 Answer

    µ= 0.5773<µ.st= 0.91

    Hope this helps

    Cuglier

    Source(s): It
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