# Work Energy Theorem Problem

1. Dec 7, 2012

### theBEAST

1. The problem statement, all variables and given/known data
Using work energy theorem, solve:

3. The attempt at a solution
The actual answer (3.11s) is exactly half of my answer. Does anyone know what I did wrong?

2. Dec 7, 2012

### grzz

Note that moment of inertia of a uniform disc about an axis through its centre and perpendicular to its plane is

$\frac{1}{2}$MR$^{2}$.

3. Dec 7, 2012

### theBEAST

Yup! That is what I used I believe.

4. Dec 7, 2012

### haruspex

There should be two factors of 1/2 - one from Iω2/2 for the KE and another from I=Mr2/2.