Question

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 1

Answer:

26.4 kg

Step-by-step explanation:

Find the radius:

Radius = Diameter ÷ 2

Radius = 3 ÷ 2 = 1.5 cm

Find the inner area of the opening:

Area = πr²

Area = π(1.5 cm)² = 2.25π cm²

Area of the outer area of the opening:

Area = πr²

Area = π(1.5 + 1)² = 6.25π cm²

Find the volume of metal in the pipe:

Volume = (6.25π - 2.25π) x 100 = 400π cm³

Find the weight:

1 cm³ = 21 g

400π cm³ = 21 x 400π = 26,400g or 26.4 kg

Answer: The weight is 26.4 kg

Answer 2

Step-by-step explanation:

Given:- Diameter of a pipe=3cm. and

it's height=1m =100cm.

Now, Radius of a pipe=3cm/2=1.5cm.it is inner radius.

then, the thinkness of pipe=1cm

outer radius=1.5+1cm=2.5cm

Volume of cast iron=πr^2h

[22/7×{(2.5)^2-(1.5)^2}×100]cm^3

[22/7×4×1×100]cm^3. =8800/7cm^3.

it is the 1cm^3 of cast iron weights=21g.

then, [8800/7×21/1000]kg =26.4kg.

(thus, 1kg=1000g).

Thanks❤❤❤.

follow me......