Question

A hollow cylindrical cast iron pipe has a length of 20 m, a thickness of 5 cm, and an outer radius of 1 m.

If 1 cubic cm of cast iron weighs 21 g, then find the weight of the pipe

Answer 1

Answer:

if one cubic cm of cast iron weighs 21g then find the weight of a cast iron pipe of lenght 1 m with a bore of 3cm and in which the thickness of the metal is 1 cm

Answer 2

We habe given that

Internal radius = 1 m - 5 cm = 95 cm

External radius = 1 m = 100 cm

Height = 20 m = 2000 cm

We know that,

Volume of cast iron,

$v = \pi( {r1}^{2} - {r}^{2} )h\\ = \frac{22}{7} ( {100}^{2} - {5}^{2} ) \times 2000 \\ \frac{22}{7} \times 9975 \times 2000 \\ = 62700000 \: {cm}^{3}$

It is given that,

$1 \: {cm}^{3}$

of cast iron weighs 21 g

We know that 1 kg=1000 g

So the weight of cast iron pipe,

$= 62700000 \times 21 \: gm \\ 1316700000 \: gm \\ = 1316.70 \: kg$

Therefore, the weight of cast iron pipe is 1316.70 kg.