Question

An iron pipe is 21 m long and its exterior diameter is 8 cm. If the thickness of the pipe is 1

cm and density of iron is 8g/cm3

, find the weight of pipe.​

Answer 1

Answer:

given that,

external diameter = 8 cm

external radius = R =4 cm

thickness= 1 cm

so, internal diameter= (8-1) cm = 7 cm

internal radius = r = 3.5 cm

volume of iron = π(R²- r²)h

= > \frac{22}{7}( {4}^{2} - {3.5}^{2} )21=>

7

22

(4

2

−3.5

2

)21

=> 247.5 cm³

weight of iron = 247.5× 8 = 1980 gram or 1.98 kg