A beam is going to be constructed by welding together the tw

A beam is going to be constructed by welding together the two equal angle sections shown. Which of the possible welded configurations shown below will lead to the highest value of the second moment of area I of the section with respect ot the horizontal axis?

All configurations will have the same value of the second moment of area.

Configuration (a) has the highest second moment of area.

Configuration (b) has the highest second moment of area.

Configuration (c) has the highest second moment of area.

Configuration (d) has the highest second moment of area.

Solution

configuration (d) has the highest second moment of area because in this section most of the material is far away from horizontal axis and as the distance of most of the material increases from the axis about which we have to find out second moment of area then second moment of area about that axis increases.

here configuration (c) has the minimum I because most of the material is on the horizontal axis (i.e axis about which we have to find out I)