Question

A solid iron pole consists of a cylinder of height 220 cm and base diameter 24 cm, which is surmounted by another cylinder of height 60 cm and radius 8 cm. Find the mass of the pole, given that 1 cm3 of iron has approximately 8 g mass. [Use $\pi = 3.14$]

Answer 1

From the figure, it can be observed that

Height (h1) of larger cylinder = 220 cm
Radius (r1) of larger cylinder =$\frac{24}{2}$= 12 cm
Height (h2) of smaller cylinder = 60 cm
Radius (r2) of smaller cylinder = 8 cm

Total volume of Pole= Volume of large cylinder + Volume of smaller cylinder
$=\pi r_1^2h_1+\pi r_2^2h_2$
$=\pi (12)^2\times220+\pi (8)^2\times60$
$=\pi [144\times220+64\times60]$
$=35520\times3.14$
$= 1,11,532.8\text{ cm}^3$

Mass of 1 cm3 iron = 8g
Mass of 111532.8 cm3 = $111532.8×8$ g = 892262.4 g = 892.262 Kg