Question

A cube-shaped block of pinewood has a surface area of 9 m${}^2$ and a density of 0.5 gcm${}^3$. Its mass equals

• A. 4500 g
• B. 4500 kg
• C. 13500 g
• D. 13500 kg

Answer 1

Answer: (D)

13500 kg

Density $\rho =0.5$ $g/c{m}^3=500$ $kg/m^3$

Length of the cube $l=\sqrt{A}=\sqrt{9}=3$ m

Thus volume of cube $V=lA=3\times 9=27$ $m^3$

$\therefore$ Mass $M=\rho V=500\times 27=13500$ kg