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Homework Help: Calculating moment of inertia

  1. Dec 6, 2009 #1
    1. The problem statement, all variables and given/known data
    The work done in accelerating a flywheel from rest to an angular speed of 14.5 revolutions per second is 22.0 kJ. What is the moment of inertia of the flywheel?


    2. Relevant equations
    ½Iω² = 22.0 kJ


    3. The attempt at a solution
    ½Iω² = 22.0 kJ
    I = (2)(22.0 kJ)/ω²
    ω = (14.5 revs/sec)
    = (14.5 revs/sec) × (2π rad/rev)
    = 29π = 91.1

    I = (2)(22)/(91.1)2
    I = 44/8300.3
    I = 0.00531
     
  2. jcsd
  3. Dec 6, 2009 #2
    You are using SI units. How many joules are there in 22kJ?
     
  4. Dec 6, 2009 #3
    Oh, thank you! I hadn't even noticed!
     
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