# Sierpinski carpet - Moment of inertia

1. Sep 9, 2009

### zl64c

Hi, its my first post here, so i say HI :D
hm, i have a little problem with moment of interia. I know, that sierpinski carpet has no area and thats why with normal situation it also has not moment of interia (MoI). but now, i have special situation: mass - m, and lenght a. O and O' is perpendicular to the plan. i think is simple integral but maybe im wrong? waiting for any ideas or any integrals to calc( love it ) :D:D

greetings form Poland

2. Sep 9, 2009

### Avodyne

Welcome to the forum!

I'm sorry to say that I don't understand your question. What exactly are you trying to compute?

3. Sep 9, 2009

### rock.freak667

Well what I am seeing is that it is basically a large square with squares in it cut out. So you can find the moment of inertia of the entire large square and then subtract the moments of inertia of the smaller squares (which may be a bit tedious as it looks)

4. Sep 10, 2009

### zl64c

yes, thats true. But i know how to calc MoI only Jx and Jy and here i have axis z. thats a problem.

5. Sep 10, 2009

### rock.freak667

By the perpendicular axis theorem, Iz=Ix+Iy

6. Sep 11, 2009

### zl64c

i just calced it. thanks

7. Oct 16, 2009