Homework Help: Moment of Inertia - Iy

1. Nov 26, 2012

aaronfue

1. The problem statement, all variables and given/known data
I was wanting to see if someone could check my calculations. I've checked out the Iy and Ix in Autodesk Inventor and what I got is wrong.

http://postimage.org/image/re825r20b/
http://postimage.org/image/vomq1c73f/
http://postimage.org/image/lkdgw1dyv/

2. Relevant equations

I believe the only one that is wrong is the triangle?

My centroids were all correct, including my areas. So I'm sure my calculations for MOI's are wrong somewhere.

Last edited: Nov 26, 2012
2. Nov 26, 2012

SteamKing

Staff Emeritus
The MOI of the triangle is wrong.
Are you supposed to calculate Iy about the tip of the triangle or about the centroid of the entire figure?

3. Nov 28, 2012

aaronfue

I was supposed to calculate Iy of the entire figure, but still wanted to calculate each shape. I was able to get the MOI of the triangle: $\frac{1}{36}$