Moment of inertia question

[hhq5000]

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. I am really stuck and don't know what to do next.

 

[Doc Al]

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.

 

[hhq5000]

Thanks so much! i just got it right on the webassign