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Rotational kinetic energy of a wheel

  1. Dec 25, 2011 #1
    1. The problem statement, all variables and given/known data

    I have a wheel with a diameter of 1.4m and the radius of gyration is 0.42m. The wheel has a mass of 13kg. Calculate maximum rotational kinetic energy.

    2. Relevant equations



    3. The attempt at a solution

    From this all i can do is calculate the moment of inertia which is the mass (x) radius of gyration squared which gives me 2.29kg/m squared.
    As far as i am aware i need the angular velocity to calculate the kinetic energy but i have no velocity figures. Any help is much appreciated
     
  2. jcsd
  3. Dec 26, 2011 #2

    Doc Al

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    Staff: Mentor

    Without more information, there's not much you can do. Did you present the full problem exactly as given, word for word?
     
  4. Dec 26, 2011 #3
    You have to know how many turns it took so you can use: [tex]\frac{1}{2}J_{\Delta}\omega^{2}=M_{\Delta}*\Delta\theta[/tex] to calculate the maximal angular speed.

    Then you can just plug it in and find your answer .

    Ps: JΔ of a wheel : [tex]J_{\Delta}=M*R^{2}[/tex]
     
  5. Dec 26, 2011 #4
    yes that is all the information that is in the question. I have previously calculated a maximum linear velocity which i now assume is what i have to use to answer the question even though it makes no reference to it. Many thanks for your replies.
     
  6. Dec 26, 2011 #5

    Doc Al

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    Staff: Mentor

    So there are other parts to this problem? Post the entire problem, start to finish.
     
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