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## Homework Statement

The flywheel of a gasoline engine is required to give up 500 J of kinetic energy while its angular velocity decreases from 650 rev/min to 520 rev/min. What moment of inertia is required?

## Homework Equations

K = (1/2) * I * w^2

K = kinetic energy

I = moment of inertia

w = angular velocity

## The Attempt at a Solution

I thought that since the engine gives up 500 J of KE (so change of 500?) I can plug in 500 for K, and the final angular velocity for w, to solve for I.

500 = (1/2) * I * ((520)/60) * 2pi)^2

I = .337 kg m^2

The correct answer is 0.600 kg m^2. What am I doing wrong here? thanks