Question

A block of iron has dimensions $2m\times 0.5m\times 0.25m$. The density of iron is $7.8gc{m}^{-3}$ . Find the mass of block.

Answer 1

Given,
[Since $1gc{m}^{-3}=1000kg{m}^{-3}$ ]
Density of iron, $d=7.8gc{m}^{-3}=7.8\times 1000kg{m}^{-3}=7800kg{m}^{-3}$ And
dimension is $2m\times 0.5m\times 0.25m$
So, Volume of the block, $V=2m\times 0.5m\times 0.25m=0.25m^3$
Using formula of density,
$\text{Density}\left(d\right)=\frac{\text{mass}\left(m\right)}{\text{volume}\left(V\right)}$
$7800kg{m}^{-3}=\frac{\text{mass}\left(m\right)}{0.25m^3}$
$\text{mass}=7800\times 0.25=1950kg$
So, mass of the block (m) = 1950 𝑘g