Hello guys, how are you?

Well, here is my doubt:

"The pendulum of a watch is formed by a thin rod of 207g and 20cm lenght and by a disc of 398g and 11cm of diameter. When the pendulum rotates around the extremity of the rod, with the plane of the disc perpendicular to the rotate axis, it's inertial moment is 0.016kg.m^2. How far from the rotate axis, is the center of the disc attached to the rod?"

First, I have to say that I found the question a little confusing... but if I understand well, I think it is this what it wants we to find:

http://s13.postimage.org/6qpmdwzzb/pendulum.jpg
As I said, this is only my interpretation. This figure wasn't on the question.

Well, my attempt:

m: mass of the rod

M: mass of the disc

Using the Steiner's Theorem:

I=I(disc)+I(rod)+(m+M)x^2

I=((MR^2)/2))+((mL^2)/12)+(m+M)x^2

Solving this equation I found x=7.13cm.

I'd like to know if I did the correct resolution, because I'm not very confident with the way I did the inertial moment and all the stuff.

Thanks in advance,

Frank.