AP BIOLOGY

Detailed explanation-1: -In the I section more than 85% of shear force is resisted by the web. Hence, The web resists the shear force and flanges resist most of the bending moment in rolled steel beams.

Detailed explanation-2: -The flanges resist bending while the web takes on the shear force. An I-beam has tapered flanges with a narrower flange than most wide flange beams, making it a lighter building material. A wide flange beam, with wider flanges and web than the I-beam, can handle more weight, but this makes it heavier overall.

Detailed explanation-3: -Clearly, the section modulus of the I-section is more than that of the rectangular cross-section for the same depth. Hence I-Section is most efficient in carrying bending moment.

Detailed explanation-4: -Thus, the rate of change of the bending moment with respect to x is equal to the shearing force, or the slope of the moment diagram at the given point is the shear at that point.