Calculate 8891

Calculate the weight of a PVC pipe with an inner diameter d = 45 mm and a length l = 3 m if the wall thickness of the pipe is s = 7.5 mm. The density of PVC is ρ = 1350 kg/m³.

Correct answer:

m =  5.0099 g

Step-by-step explanation:

$$\begin{gathered} d=45\text{mm}\to \text{m}=45:1000\text{m}=0.045\text{m} \\ s=7.5\text{mm}\to \text{m}=7.5:1000\text{m}=0.0075\text{m} \\ \rho =1350{\text{kg/m}}^3 \\ l=3\text{m} \\ {r}_1=d/2=0.045/2=\frac{9}{400}=0.0225\text{m} \\ {r}_2=r_1+s=0.0225+0.0075=\frac{3}{100}=0.03\text{m} \\ S=\pi \cdot r_2^2-\pi \cdot r_1^2=3.1416\cdot 0.03^2-3.1416\cdot 0.0225^2\doteq 0.0012{\text{m}}^2 \\ V=S\cdot l=0.0012\cdot 3\doteq 0.0037{\text{m}}^3 \\ m=V\cdot \rho =0.0037\cdot 1350=5.0099\text{g} \end{gathered}$$

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