The length of a metallic tube is 1 metre, its thickness is 1 cm and its inner diameter is 12 cm. Find the weight of the tube if the density of the metal is 7.7 grams per cubic centimetre.
Hint. Weight of 1 cm3 of metal = 7.7 g.
Its volume =
It is given in the question that,
Length = 1m
= 100cm
Inner diameter = 12 cm
Inner Radius = 6 cm
Hence,
Inner volume =
= 
= 11314.286 cm3
Thickness = 1 cm
Total radius = 7 cm
Now,
We can calculate the following measurements:
Total volume =
= 
= 15400 cm3
Now,
Volume of the tube = total volume – inner volume
= 11314.286 – 15400
= 4085.714 cm3
We have,
Density of the tube = 7.7 g/cm3
Therefore,
Weight of the tube = volume × density
= 4085.714 × 7.7
= 31459.9978 g
= 31.46 kg
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