Question

the length of a metallic tube is 1 metre , it's thickness is 1 cm and it's inner diameter is 12cm . find the weight of the tube if the density of the metal is 7.7 grams per cubic centimetres,

Answer 1

Inner diameter = 12 cm
Therefore, radius = 6 cm
Thickness = 1 cm
External radius = thickness + inner radius
=1 + 6 = 7 cm.
Length of tube = 1 m = 100 cm
Now, volume of tube = π(R² - r²)h
22/7 * (7² - 6²) * 100
22/7 * 13 * 100 = 4085.71 cm³
Density of metal per cm³ = 7.7 g
Weight of tube = 7.7 g × 4085.71 = 31868.538 g = 31.868 kg

Answer 2

• inner diameter = 12 cm

Therefore, radius = 6 cm

• Thickness = 1 cm

External radius = thickness + inner radius

• =1 + 6 = 7 cm.

Length of tube = 1 m = 100 cm

• Now, volume of tube = π(R² - r²)h

22/7 * (7² - 6²) * 100

22/7 * 13 * 100 = 4085.71 cm³

• Density of metal per cm³ = 7.7 g

Weight of tube = 7.7 g × 4085.71

                          = 31868.538 g

                          = 31.868 kg