radius of an iron sphere is 0.21 cm If density of iron is 7.80g/cc calculate mass

Solution:

Radius of iron sphere , r = 0.21 cm;

Density of iron is, d = 7.80g/cc

Mass of the iron sphere, m = ?

$$\begin{gathered} Mass = Volume *\hspace{0.17em}Density \\ M = \frac{4}{3}{\mathrm{\pi r}}^3 * 7.80 \\ \mathrm{M} = \frac{4}{3}*\hspace{0.17em}\frac{22}{7}*\hspace{0.17em}{\left(0.21\right)}^3 *\hspace{0.17em}7.80 \\ \mathbf{M}\mathbf{ }\mathbf{=}\mathbf{ }\mathbf{0}\mathbf{.}\mathbf{303}\mathbf{ }\mathbf{g} \end{gathered}$$