Question

An iron pipe is 42 cm long and it exterior radius is 4cm If the thickness of the pipe is 1 cm and iron weight s 100 gram per cm cube then the weight of the pipe is ​

Answer 1

Answer:

First we calculate the total surface area of the pipe.

TSA = Inner surface area + Outer surface area + Area of two rims

Outer radius = 4 cm = R

Thickness = 1 cm

Inner radius = R - T

= 4 - 1

= 3 cm = r

$= \pi R^{2} + \pi r^{2} + 2\pi r^{2}$

$= \pi [R^{2} + r^{2}] + 2\pi r^{2}$

$= \pi [4 + 3] + 2 * \frac{22}{7} * 3$

$= \frac{22}{7} * 7 + \frac{44}{7} * 3$

$= 22 + 18.85$

$= 40.85$ $cm^{3}$

Weight of iron = 100 grams/cm^3

Total weight = 100 × 48.05

= 4805 grams OR 4.805 kg

Hope it helps

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