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## Homework Statement

You have been assigned the task of designing a flywheel capable of storing

the translational kinetic energy of a 600 kg car traveling at 100 km/hr. The

flywheel is to be manufactured out of steel and the maximum rotational

speed is 12,000 rpm.

a. Assuming that the flywheel is a uniform cylindrical disk 50 mm in

thickness, calculate the mass and diameter of the flywheel.

## Homework Equations

ω=2π/60

TKE=1/2mv^2

Ig=1/2mr^2

RKE=1/2Ig*ω^2

## The Attempt at a Solution

Solving for ω[/B]

12000rpm*2pi/60=1256.6 rad/s

**Solving for energy TKE**

100*1000/3600=27.8m/s

1/2*600*27.8m/s=231481J

**Solving for Ig(moment of inertia flywheel)**

RKE=1/2Ig*ω^2

RKE=1/2Ig*ω^2

231481=1/2Ig*1256.6^2

Ig=0.293KG

At this point I'm not sure how to go further.