Question

Iron has a specific gravity of 7.8. Suppose you have a solid cube-shaped piece of iron and know that its mass is 56 kg. The volume of a cube with edge a is

Answer 1

The volume of iron cube

$$V=\frac{m}{\rho}=\frac{m}{1000\:\rm{SG}}$$

$$=\frac{56\:\rm{kg}}{1000\times 7.8\:\rm{kg/m^3}}=7.179\times 10^{-3}\:\rm{m^3}$$