Homework Help Forum: Physics Help!

Posted by Sally on Thursday, November 5, 2009 at 6:35pm.

Sorry I've tried 3 different ways to answer this and all have been wrong, please help me out! The moment of inertia of a 1.1 kg bicycle wheel rotating about its center is 0.15 kg*m^2 What is the radius of this wheel, assuming the weight of the spokes can be ignored?

• Physics Help! - bobpursley, Thursday, November 5, 2009 at 6:37pm

  I would model the wheel as a hoop> Mr^2=.15 r= sqrt (.15/1.1)= 37 cm

  
  

• Physics Help! - MathMate, Thursday, November 5, 2009 at 6:40pm

  It would be nice if you posted your three ways to calculate the quantity, and the values that you obtained. Moment of inertia =Σmr² In this case, the weight is all distributed at the rim, ignoring spokes, so 1.1 kg r²=0.15 kg-m² Solve for r.

  
  

• Physics Help! - Sally, Thursday, November 5, 2009 at 6:45pm

  Thank you so much guys!!!

  
  

• Physics Help! - MathMate, Thursday, November 5, 2009 at 7:58pm

  You're welcome, Sally!

  
  

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