Asbestos is a fibrous silicate mineral with remarkably high tensile strength.
But it is no longer used because airborne asbestos particles can cause lung
cancer. Grunerite, a type of asbestos, has a tensile strength of \(3.5 \times
10^{2} \mathrm{~kg} / \mathrm{mm}^{2}\) (thus, a strand of grunerite with a
\(1-\mathrm{mm}^{2}\) cross-sectional area can hold up to \(3.5 \times 10^{2}
\mathrm{~kg}\) ). The tensile strengths of aluminum and Steel No. 5137 are \(2.5
\times 10^{4} \mathrm{lb} / \mathrm{in}^{2}\) and \(5.0 \times 10^{4}
\mathrm{lb} / \mathrm{in}^{2},\) respectively. Calculate the cross-sectional
areas (in \(\mathrm{mm}^{2}\) ) of wires of aluminum and of Steel No. 5137 that
have the same tensile strength as a fiber of grunerite with a crosssectional
area of \(1.0 \mu \mathrm{m}^{2}\).