Question

Two beams have the same width but the first beam has double the depth of the second beam. The elastic strength of the first beam compared to the second beam will be

• A. Four times
• B. Double
• C. Eight times
• D. Half

Answer 1

Answer:

A. Four times

Given: $d_{A} = 2d_{B}$

Sectional Modulus $(Z): Z=\frac {bd^2}{6} \Rightarrow \frac {Z_B}{Z_A}=\frac {d_B^2}{d_A^2}=\frac{(d_B)^2}{(2d_B)^2}=\frac14 \Rightarrow Z_A=4Z_B$