Question

A shot-put is a metallic sphere of radius $4.9cm$. If the density of the metal is $7.8gperc{m}^3$, find the mass of the shot-put. (Take $\pi =22/7$)

Answer 1

To find mass, we have to find volume of sphere.

Radius of sphere$=r=4.9$cm

Volume of the sphere$=\frac{4}{3}\pi r^3$

$=\frac{4}{3}\times \frac{22}{7}\times 4.9\times 4.9\times 4.9=493.0053{cm}^3=493{cm}^3$(approx)

now, Density$=\frac{Mass}{Volume}$

$\Rightarrow 7.8=\frac{Mass}{493}$

$\Rightarrow$ Mass$=7.8\times 493=3845.44$gms