Question

Calculate the weight of a brass hollow hemisphere if the inner diameter is 14 cm and thickness is 1 mm, and whose density is 17.3 $g/c{m}^3$.

• A. 540.45 g
• B. 640.45 g
• C. 440.45 g
• D. 1080.9 g

Answer 1

The correct option is A 540.45 g

Weight of brass hemispherical shell(w) = weight density $\times$ volume.

Volume of hemispherical shell 'V' is $\frac{2}{3}\pi (r_2^3-r_1^3)$.
where,
$r_2$ is outer radius and $r_1$ is inner radius.
Thickness of shell 't' is $r_2-r_1$.
$r_1=7cm$
$r_2=r_1+t=7+0.1cm=8cm$
$V=\frac{2}{3}\pi ({7.1}^3-7^3)=31.24c{m}^3$
w = weight density $\times$ volume
= 17.3 $g/c{m}^3$ $\times$ 31.24
= 540.45 g