Cylindrical column

What is the mass of a reinforced concrete cylindrical column with a radius of 30 cm and a height of 4.5 m if the density of reinforced concrete is 2400 kg/m³? Round the result to whole kilograms.

Correct answer:

m =  3054 kg

Step-by-step explanation:

$$\begin{gathered} r=30\text{cm}\to \text{m}=30:100\text{m}=0.3\text{m} \\ h=4.5\text{m} \\ \rho =2400{\text{kg/m}}^3 \\ {S}_1=\pi \cdot r^2=3.1416\cdot 0.3^2\doteq 0.2827{\text{m}}^2 \\ V=S_1\cdot h=0.2827\cdot 4.5\doteq 1.2723{\text{m}}^3 \\ m=\rho \cdot V=2400\cdot 1.2723=3054\text{kg} \end{gathered}$$

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