A hollow copper pipe is 22 cm long and its external diameter is 28 cm.If the thickness of the pipe is 3 cm and iron weighs 8.5 g/cm3 , then the weight of the pipe is closest to:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 44 kg
| Understanding | Formula used |
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R = 28/2 = 14cm r = 14 - 3 = 11cm Volume of pipe = 22 × 22 ×(142 - 112)/7 Volume of pipe =484 × 75/7 = 5185.714 Weight of pipe = 5185.714 × 8.5 = 44078.56g or 44kg |
Radius = Diameter/2 Internal radius= External radius - Thickness Volume of hollow cylinder = πh(R2 - r2) |