Finding Second Moment of Inertia for Shaded Area Through Centroid?

[werson tan]

Homework Statement

determine the second moment of inertia about the horizontal axis and vertical axis for the shaded area with respect to x and y axes through the centroid of the area .

Homework Equations

The Attempt at a Solution

Since the x and y axes is drawn thru centroid , why not the y for part 1 = 0mm ? y for part 2 = -30mm?

 

[SteamKing]

Homework Statement

determine the second moment of inertia about the horizontal axis and vertical axis for the shaded area with respect to x and y axes through the centroid of the area .

Homework Equations

The Attempt at a Solution

Since the x and y axes is drawn thru centroid , why not the y for part 1 = 0mm ? y for part 2 = -30mm?

Because the axes being used for the calculation are not the same ones shown in Fig. 6.7. The calculation axes are shown at the lower right-hand part of the page, just above the table.

You must read the text in order to follow what is going on; you can look at one picture and assume it applies regardless.

 

[haruspex]

You must read the text in order to follow what is going on; you can look at one picture and assume it applies regardless.

You meant 'cannot', right?

 

[SteamKing]

You meant 'cannot', right?

Yes.