Question 1206289
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A cylindrical drain pipe has internal and external diameters of 6.4cm and 7.6cm respectively. 
Calculate the mass of the pipe per meter if it is made of metal of density 8 g/cm^3.
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<pre>
You calculate first the area of the cross section

    area = {{{pi*(D^2/4 - d^2/4)}}} = {{{3.14159*(7.6^2/4-6.4^2/4)}}} = 13.194678 cm^2.



Then you calculate the volume of the 1 meter metallic pipe by multiplying the cross area by 100 cm

    volume = 100*area = 100*13.194678 = 1319.4678 cm^3.



Then you multiply the volume by the density and get the <U>ANSWER</U>

    the mass per meter = 8*1319.4678 = 10555.7 gram  = 10.556 kg (rounded).
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Solved.