Question

Find the weight of a lead pipe 3.5 m long , if the external diameter of the pipe is 2.4 cm and the thickness of the lead is 2 mm and 1 cu cm of lead weights 11 g .

Answer 1

We know that,

$R=\frac{d}{2}=\frac{2.4}{2}=1.2cm$

External Radius $\left(R\right)=1.2cm$

Thickness $=2mm=0.2cm$

Inner Radius $\left(r\right)=1.2-0.2$

$=1cm$

Height (h) $=3.5cm=350cm$

Volume of hollow cylinders $=\pi (R^2-r^2)h$

$=\frac{22}{7}\times ({1.2}^2-1^2)\times 350$

$=\frac{22}{7}\times (1.44-1)\times 350$

$=22\times 0.44\times 50$

$=22\times \frac{44}{100}\times 50$

$=484c{m}^3$

Weight of $1c{m}^3=11g$

Weight of $484c{m}^3=484\times 11$

$=5324g$