Cu wire

Copper wire has a length l = 820 m and diameter d = 10 mm. Calculate the weight if the density of copper is ρ = 8500 kg/m³. Please result round to one decimal place.

Correct answer:

m =  547.4 kg

Step-by-step explanation:

$$\begin{gathered} \rho =8500{\text{kg/m}}^3 \\ l=820\text{m} \\ d=10\text{mm}\to \text{m}=10:1000\text{m}=0.01\text{m} \\ S=\pi \cdot (d/2{)}^2=3.1416\cdot (0.01/2{)}^2\doteq 0.0001{\text{m}}^2 \\ V=S\cdot l=0.0001\cdot 820\doteq 0.0644{\text{m}}^3 \\ m=\rho \cdot V=8500\cdot 0.0644=547.4\text{kg} \end{gathered}$$

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