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Homework Help: Magnitude of Torque

  1. Mar 25, 2008 #1
    1. The problem statement, all variables and given/known data

    Massive spinning flywheels (disks) can be used for storing energy. Consider a flywheel with a diameter of 1.10 m and a mass of 510 kg. A constant force of magnitude F is applied tangentially to the rim of the flywheel to accelerate it from rest to 4.00 x 103 rev/min during 2.85 min.

    (b) What magnitude of torque is necessary to cause this angular acceleration?

    2. Relevant equations

    I = mR[tex]^{2}[/tex]
    [tex]\tau[/tex] = I[tex]\alpha[/tex]

    3. The attempt at a solution

    I = mR[tex]^{2}[/tex]
    I = (510kg)[tex]\ast[/tex](.55m)[tex]^{2}[/tex]
    I = 154.275 kgm[tex]^{2}[/tex]

    [tex]\tau[/tex] = I[tex]\alpha[/tex]
    [tex]\tau[/tex] = (154.275kgm[tex]^{2}[/tex])\ast(2.449rad/s[tex]^{2}[/tex]
    [tex]\tau[/tex] = 377.819 Nm

    The answer was incorrect. Also the angular acceleration was derived from part a and is the correct number. Thanks for the help.
     
  2. jcsd
  3. Mar 25, 2008 #2
    the Tau and Alpha symbols are not suppose to be superscripts. i screwed up the tex
     
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