Rotational Kinetic Energy Problem

[Loppyfoot]

Homework Statement

A thin uniform-density rod whose mass is 3.8 kg and whose length is 3.0 m rotates around an axis perpendicular to the rod, with angular speed 34 radians/s. Its center moves with a speed of 10 m/s.

(a) What is its rotational kinetic energy?
(b) What is its total kinetic energy?

Homework Equations

Well I know that Krot= 1/2I* w2. But when I try to use this equation, I get the wrong answer. I also know that I= 1/2mr^2

The correct answers are:

(a)= 1650 J
(b)= 1840 J

Does anyone have any idea on where I'm going wrong?

The Attempt at a Solution

 

[ashishsinghal]

I also know that I= 1/2mr^2

from where did you get this?

 

[Loppyfoot]

Moment of Inertia= mr^2. Sorry.

 

[ashishsinghal]

How did you get that?

 

[Loppyfoot]

That's not the equation? Then what equation would I use to represent the rod with moment of inertia?

 

[ashishsinghal]

moment of inertia of a uniform rod is ml^2/12 about its center of mass.