- #1

Ignitia

## Homework Statement

A 1000-kg car has four 10-kg wheels. When the car is moving, what fraction of its total kinetic energy is due to rotation of the wheels about their axles? Assume that the wheels the same mass and size.

## Homework Equations

Rolling Wheel:

K=1/2 I

_{com}ω

^{2}+ 1/2mv

^{2}

Inertia for Wheel:

I=1/2mv

^{2}

v=ωr

ω=v/r

## The Attempt at a Solution

(Per wheel)

K=1/2 I

_{com}ω

^{2}+ 1/2mv

^{2}

K=1/2 [1/2mv

^{2}*vSUP]2[/SUP]/r

^{2}+ mv

^{2}]

K=1/2 [1/2mv

^{2}+ mv

^{2}]

K=1/2 [3/2mv

^{2}]

K=3/4 mv

^{2}]

The book states the answer to be 0.020

How?