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Moment of inertia question

  • Thread starter hhq5000
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  • #1
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Homework Statement



When a ceiling fan rotating with an angular speed of 2.40 rad/s is turned off, a frictional torque of 0.227 Nm slows it to a stop in 6.65 s. What is the moment of inertia of the fan?


Homework Equations





The Attempt at a Solution



In almost all of the moment of inertia equations, they involve a radius. there is no radius given in the problem. i tried to use K= 1/2 I w^2. Im really stuck and dont know what to do next.
 

Answers and Replies

  • #2
Doc Al
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You don't have the data to compute the moment of inertia directly. Instead, deduce the moment of inertia by applying Newton's 2nd law for rotation. Hint: First compute the angular acceleration using kinematics.
 
  • #3
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Thanks so much! i just got it right on the webassign
 

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