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 iron weight is 8 g/cm?, find the weight of pipe.​

Answer 1

$\small\bold{\underline{\sf{\purple{Given:-}}}}$

• Height of the pipe = 21m = 2100cm
• Exterior Radius(R)= 8/2 = 4cm
• Thickness of the pipe = 1cm
• Internal radius (r) = external radius - Thickness = 4 - 1 = 3cm.
• Weight of iron = 8g/cm.

$\small\bold{\underline{\sf{\red{To\:Find:-}}}}$

• The weight of the Pipe

$\small\bold{\underline{\sf{\pink{Formula\:used:-}}}}$

Volume of Cylinder = πr²h

$\small\bold{\underline{\sf{\blue{solution:-}}}}$

Now,

→ Volume of pipe = Volume of external cylinder - Volume of internal cylinder.

→ Volume of pipe = πR²h - πr²h

→ πh ( R² - r² )

→$\rm{\dfrac{22}{7}\times{210} ( 4^2 - 3^2)}$

→$\rm{22\times{300} ( 16 - 9)}$

→$\rm{ 6600\times{7}}$

→$\rm{ 46200cm^{3}}$

Hence, The Volume of the pipe is 46200cm³.

→ weight of iron pipe per cm = 8g

Now,

→ Weight of 4620cm³ Pipe = 46200 × 8 = 369600g

Hence, The weight of pipe is 369.60kg