Question

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.

Answer 1

It is given in the question that, 

Length = 1m 

= 100cm 

Inner diameter = 12 cm 

Inner Radius = 6 cm 

Hence, 

Inner volume = πr₁²h 

Thickness = 1 cm 

outer radius = 7 cm 

Now, 

We can calculate the following measurements: 

Total volume = πr₂²h 

Now, 

Volume of the tube = total volume – inner volume 

= πr₂²h- πr₁²h 

= πh(r₂² - r₁²)= 3.14 × 100 × (7² - 6²) = 3.14 × 100 × (49 - 36)

= 314 × 13

= 4082 cm³ 

We have, 

Density of the tube = 7.7 g/cm³ 

Therefore, 

Weight of the tube = volume × density 

= 4082 × 7.7 

= 31431g 

= 31.43 kg