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 102 \ \mathrm { kg } / \mathrm { mm } 23.5×102 kg/mm2 (thus, a strand of grunerite with a 1-mm2 cross-sectional area can hold up to 3.5 \times 102 \mathrm { kg } )3.5×102kg) . The tensile strengths of aluminum and Steel No. 5137 are 2.5 \times 104 \ lb/in22.5×104 lb/in2 and 5.0 \times 104 \ { lb } / \mathrm { in } 25.0×104 lb/in2 respectively. Calculate the cross-sectional area (in mm2) of wires of aluminum and of Steel No. 5137 that have the same tensile strength as a fiber of grunerite with a cross-sectional area of 1.0 \ \mu m 2 .1.0 μm2.
