Question

A shotput is a metalic sphere of radius $4.9cm$. If the density is $6.9g/c{m}^3$,then the mass of the shotput in kg is:

• A. $3.401kg$
• B. $3kg$
• C. $4kg$
• D. $34kg$

Answer 1

Answer: (A)

$3.401kg$

Radius of the shotput $r=4.9cm$
Volume of the shotput $=\frac{4}{3}\pi r^3$
$=\frac{4}{3}\times \frac{22}{7}\times 4.9\times 4.9\times 4.9{cm}^3$
$=493.0053{cm}^3$

Density of the metal $=6.9g{cm}^{-3}$
So, the mass of the shotput $=$ Volume $\times$ Density
$=493.0053\times 6.9g$
$=3401.7366g$
$=3.401kg$