Question

The diameter of a metallic ball is 4.2 cm. What is the mass of the ball, if the density of the metal is 8.9 g per cm3 ?

Answer 1

Radius of the metallic ball, r = $\frac{4.2}{2}$ cm = 2.1cm
The volume of the metallic ball = $\frac{4}{3}\pi r^3$
= $\frac{4}{3}$ × $\frac{22}{7}$ × 2.1cm × 2.1cm × 2.1cm
= 38.808 cm³

Mass = Volume × Density
Mass of the metallic ball = 38.808 cm3 × 8.9g / cm³
= 345.3912 g
= 345.39 g
Hence, the mass of the ball is 345.39 g (approximately).