Answer
for AISI 1018 CD steel,
specific modulus = $\frac{E}{y}$ = 106.38 * $10^{6}$ inches
for 2011-T6 aluminum,
specific modulus = $\frac{E}{y}$ = 106.12 * $10^{6}$ inches
for Ti-6Al-6V titanium,
specific modulus = $\frac{E}{y}$ = 10312 * $10^{6}$ inches
for ASTM No. 49 gray cast iron,
specific modulus = $\frac{E}{y}$ = 55.77 * $10^{6}$ inches
Work Step by Step
All data necessary which is stiffness E in $Mpsi$ and unit weight w in $lbf/inch^{3}$ can be found in table A-5. From these units, we will get our answer in inches
for AISI 1018 CD steel,
specific modulus = $\frac{E}{y}$ = $\frac{30 * 10^{6}}{0.282}$ = 106.38 * $10^{6}$ inches
for 2011-T6 aluminum,
specific modulus = $\frac{E}{y}$ = $\frac{10.4 * 10^{6}}{0.098}$ = 106.12 * $10^{6}$ inches
for Ti-6Al-6V titanium,
specific modulus = $\frac{E}{y}$ = $\frac{16.5 * 10^{6}}{0.16}$ = 10312 * $10^{6}$ inches
for ASTM No. 49 gray cast iron,
specific modulus = $\frac{E}{y}$ = $\frac{14.5 * 10^{6}}{0.26}$ = 55.77 * $10^{6}$ inches
