Answer:
Step-by-step explanation:
You want the volume and weight of a 3 m pipe with an internal radius of 4 cm and a thickness of 2 cm, given the density is 2.5 g/cm³.
Volume
The volume is the product of the length and the area of the cross section. The area of the cross section is the difference in areas of the circles with the outer radius and the inner radius.
A = πr₂² -πr₁²
A = π((4+2)² -4²) = 20π . . . . cm²
The volume is the product of this and the length:
V = A·l = (20π cm²)(300 cm) = 6000π cm³
V ≈ 18850 cm³
The volume of metal is about 18850 cm³.
Weight
The weight is the product of the volume and density.
weight = (18850 cm³)(2.5 g/cm³) ≈ 47.1 kg
The weight of the pipe is about 47.1 kg.
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Additional comment
The calculator display shows the calculations to full precision. The units are cm³ for volume and g for weight. You may need to round your results differently, or use different units than shown above. 1 kg = 1000 g; 1 liter = 1000 cm³.
