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Are Problem The Feature Box in this chapter introduced spider silk as an impress

ID: 2088632 • Letter: A

Question

Are Problem The Feature Box in this chapter introduced spider silk as an impressive natural material with a specific strength greater than structural steel. Given a tensile strength of a particular spider silk as 1.2 x 103 MPa with a density of 1.30 Mg/m3, calculate its specific strength and compare that result with the value for 1040 steel in Table 1 Table 1 Specific Strengths (Strength/Density) specific strength Group Material Noncomposites 1040 steela 9.9 x 106 (0.39 x 106) 16.9 x 106 (0 67 x 106) 2048 plate aluminuma

Explanation / Answer

Specify strength is obtained as yield strength/density

From given data ss for spider silk = (1.2*10^3*10*6 Pa)/(1.3*10^6 g/m^3)

=923.0769 Nm/gram

To compare this with given values in table we need to convert units to mm

Since mass*gravity = force we can divide this term by gravitational constant to get units as meter

1kg * g = 1N

We are using grams in denominator so 1g* g = 1/1000 N

Also we need to convert 1m to 1000 mm

Finally we get specific strength as 94.095505 *10^6 mm

Which is greater than both materials given in table

With respect to steela spider silk is 9.505 times better

With respect to aluminuma spider silk is 5.5678 times better