- #1

Arejang

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**[SOLVED] moment of inertia**

## Homework Statement

The flywheel of a gasoline engine is required to give up 750 J of kinetic energy while its angular velocity decreases from 870 rev/min to 410 rev/min.

What moment of inertia is required?

## Homework Equations

[tex]I=\frac{2K}{\omega^{2}}[/tex]

## The Attempt at a Solution

I'm not sure how to derive the rad/sec used in this equation. I've converted both 870 rev/min and 410 rev/min to radians before attempting the problem (91.1 rad/sec and 42.9 rad/sec respectively). I've tried taking the difference between the two, then attempting the average, then just using the final radial velocity and ignoring the initial. I'm not sure what to do at the moment. Can anyone help?