Question

The diameter of a metallic ball is $4.2cm.$ What is the mass of the ball, if the density of the metal is $8.9g/c{m}^3$?
[Assume $\pi =\frac{22}{7}$]

Answer 1

Radius (r) of the metallic ball

$=\left(\frac{4.2}{2}\right)cm=2.1cm$

Volume of the metallic ball (Spherical in shape)

$=\frac{4}{3}\pi r^3$

$=[\frac{4}{3}\times \frac{22}{7}\times (2.1{)}^3]c{m}^3$

$=38.808c{m}^3$

$\text{Density}=\frac{\text{Mass}}{\text{Volume}}$

$\text{Mass= Density}\times \text{Volume}$

$=(8.9\times 38.808)g$

$=345.3912g$

Hence, the mass of the ball is $345.3912g$ (approximately).