고체역학 (Gere) — Stresses in Beams (Basic Topics): Problem 5.6-21

5.6-21 A steel plate (called a cover plate) having cross-sectional dimensions 200 mm \(\times\) 12 mm is welded along the full length of the bottom flange of a HE 260B wide-flange beam (see figure, which shows the beam cross section). What is the percent increase in the smaller section modulus (as compared to the wide-flange beam alone)?