A cylindrical pipe, which is open from both sides, is made of iron she

1.	A cylindrical pipe, which is open from both sides, is made of iron sheet of thickness 2 cm. If external diameter is 16 cm and height is 100 cm, then find the total iron used in making the pipe?
Answer» External diameter = 16 cm. External radius (R) = 16/2 cm. = 8 cm. Thickness of sheet = 2 cm. ∴ Inner radius (r) = 8 – 2 = 6 cm. Height (h) = 100 cm. ∴ Used iron = External Volume – Internal Volume = πR²h – πr²h = π (R² – r²) h = 22/7 {(8)² – (6)²} 100 = 22/7 x 28 x 100 = 8800 cm³

A cylindrical pipe, which is open from both sides, is made of iron sheet of thickness 2 cm. If external diameter is 16 cm and height is 100 cm, then find the total iron used in making the pipe?

Answer»

External diameter = 16 cm.

External radius (R) = 16/2 cm. = 8 cm.

Thickness of sheet = 2 cm.

∴ Inner radius (r) = 8 – 2 = 6 cm.

Height (h) = 100 cm.

∴ Used iron = External Volume – Internal Volume

= πR²h – πr²h

= π (R² – r²) h

= 22/7 {(8)² – (6)²} 100

= 22/7 x 28 x 100

= 8800 cm³