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DYNAMICS - CASE STUDY SOLUTION


Problem Graphic

 


Problem Diagram

 

The Principle of Work and Energy for a rotating body can be applied to this problem using

     T1 + ΣU1-2 = T2

The applied work for a constant moment is

     U = M θ = (100 N-m) (4.459 rad)

        = 445.9 N-m

Now the input energy is known, the change in kinetic energy needs to be determined,

     Tstart = T1 = 0

     Tfinish = T2 = 1/2 m vG2 + 1/2 IG ω2

              = 0 + 0.5 IG (1.784 rad/s)2

             = (1.591 /s2) IG

Equating the work done to the change in kinetic energy gives

     0 + 445.9 N-m = (1.591 /s2) IG

Solving for IG gives

     IG = Iz = 280.3 kg-m2

     
   
 
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