Wood lumber

Wooden lumber is 4 m long and has a cross-section square with a side of 15 cm.

Calculate:
a) the volume of lumber
b) the weight of the lumber if 1 m³ weighs 790 kg

Correct answer:

V =  0.09 m³
m =  71.1 kg

Step-by-step explanation:

$$\begin{gathered} l=4\text{m} \\ a=15\text{cm}\to \text{m}=15:100\text{m}=0.15\text{m} \\ V=l\cdot a^2=4\cdot 0.15^2=0.09{\text{m}}^3 \end{gathered}$$

$$\begin{gathered} \rho =790{\text{kg/m}}^3 \\ m=\rho \cdot V=790\cdot 0.09=71.1\text{kg} \end{gathered}$$

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