How Do You Find the Centroid of a Structural Shape with C-Beams?

[bradycat]

I have a problem trying to find the centroid.
I have a plate that is 8in wide and .5 in thick.
Then 2- C beams (C8x11.5) placed at each end of the 8in beam with the tips facing each other. They do not go beyond the 8 inches. So it's like a U as an example with the tips facing each other.

I figured out the centroid of the plate, but not sure what to do or figure out the C beams. to find the centroid?
is my equation like this.
Aty(bar)= A1ybar1 + (A2ybar2 X2)
y bar means the line that goes above the Y, as I can't insert it.
But if you know this, you know what I mean anyways.

Any help would be great, thanks.
Joanne

 

[ideasrule]

Can you post a picture? I'm quite confused as to how this is configured.

Remember that you can separate the object into smaller portions, find the center of mass of each portion, and then find the center of mass of the entire object by considering each portion to be a point mass at its COM. For example, if your object is composed of 2 rectangles with center of mass x1 and x2, the center of mass of the entire object is just (m1*x1+m2*x2)/(m1+m2).

 

[bradycat]

Here is the picture of the item I am talking about. #4 on the sheet of course.

I get an answer x bar as 1.85 and y bar 2.92.

I have for y bar = 4(.25) + 2(3.38X4.5) / 10.76

I have for x bar = (4x4) = 2(3.38x.571) / 10.76

From the american standard channels for C 8 X 11.5 Area is 3.38, Depth is 8 and X bar is .571.

do I have the correct answers??