Question:
A hemispherical bowl is made of steel 0.5 cm thick. The inside radius of the bowl is 4 cm. Find the volume of steel used in making the bowl.
Solution:
Internal radius of the hemispherical bowl = 4 cm
Thickness of a the bowl = 0.5 cm
Now, external radius of the bowl = (4 + 0.5 ) cm = 4.5 cm
Now, volume of steel used in making the bowl = volume of the shell
$=\frac{2}{3} \pi\left(4.5^{3}-4^{3}\right)$
$=\frac{2}{3} \times \frac{22}{7} \times(91.125-64)$
$=\frac{2}{3} \times \frac{22}{7} \times 27.125$
$=56.83 \mathrm{~cm}^{3}$
∴ 56.83 cm3 of steel is used in making the bowl .
Click here to get exam-ready with eSaral
For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.