Question

what metal is the part with a mass of 7.8 kg and a volume of 1000 cm³ made of

Answer 1

Given:

$V=1000\:\rm cm^3=1*10^{-3}\: m^3$

$m=7.8\:\rm kg$

The mass density

$$\rho=\frac{m}{V}=\rm\frac{7.8\: kg}{1*10^{-3}\: m^3}=7800\: kg/m^3$$

Answer: iron