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Newtons Laws and acceleration

  1. Oct 29, 2009 #1
    The pine tree air freshener hanging from the rear view mirror makes an angle of 27.9 degrees with the vertical while a car is acceleration

    a)What is the car's acceleration

    ax=gsin(theta)=9.80*sin(27.9)=4.59

    b)What is the tension in the string of the 100g air freshener?

    ax=T/m=4.59(100)=T

    T=458 (Or does the mass always have to be in kg?) T=.458
     
  2. jcsd
  3. Oct 29, 2009 #2

    rl.bhat

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    According to the law of inertia, when the car moves forward with an acceleration a. the freshener moves with the same acceleration in reverse direction. If T is the tension in the string, them in the equilibrium condition
    ma = T*sinθ and mg = T*cosθ. Here m must be in kg.
    Now solve for T and a.
     
  4. Oct 29, 2009 #3
    .10=T(cos(27.9)) T=.11315

    .10a=.11315(sin(27.9)) a=.529

    Is this correct?
     
  5. Oct 29, 2009 #4

    rl.bhat

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    No. It is not correct.
    0.10*g = T(cos(27.9))
     
  6. Oct 30, 2009 #5
    .10(9.80)=T(cos(27.9)) T=1.11

    a=T/m a=11.1
     
  7. Oct 30, 2009 #6

    rl.bhat

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    Write down the units.
    Check the calculations. T*sinθ = ma.
     
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