Question

The inner diameter of a cylindrical wooden pipe is 24 cm and its outer diameter is 28 cm. The length of the pipe is 35 cm. Find the mass of the pipe, if 1 cm³ of wood has a mass of 0.6 g. 

Answer 1

Here, inner radius (r) = 24/ 2 cm = 12 cm 

Outer radius (R) = 28/ 2 cm = 14 cm, h = 35 cm 

Volume of the wood used in the pipe = π(R² – r²) h 

= 22/ 7 [(14)⁴ – (12)²] × 35 cm³ 

= 22/ 7 × 26 × 2 × 35 cm³ = 5720 cm³ 

Mass of 1 cm³ of wood = 0.6 g 

∴ Mass of 5720 cm3 of wood = 0.6 × 5720 g = 3432 g = 3.432 kg Ans.