Question

The diameter of a metallic ball is $4.2cm$. What is the mass of the ball, if the density of the metal is $8.9gperc{m}^2$ ? (Assume $\mathrm{\pi }=\frac{22}{7}$)

Answer 1

Step : Find the mass of the ball.

Diameter of a metallic ball $4.2cm$

Therefore radius of the metallic ball, $r=\frac{4.2}{2}=2.1cm$

We know that ,

volume of the metallic ball $=\frac{4}{3}{\mathrm{\pi r}}^3$

$$\begin{gathered} =\frac{4}{3}x\frac{22}{7}x{(2.1)}^3 \\ =38.808c{m}^3 \end{gathered}$$

$Mass=densityxvolume$

$$\begin{gathered} =(8.9\times 38.808) \\ =345.3912g \end{gathered}$$

Hence, the mass of the ball is $345.3912g$.