Question

Find the weight of a hollow sphere of metal having internal and external diameters as 20 cm and 22 cm, respectively if 1 cm3 of metal weighs 21g.

Answer 1

Answer:

The weight of a hollow sphere is 29.13 kg

Step-by-step explanation:

SOLUTION :  

Given :  

Internal Diameter of hollow sphere = 20 cm

Internal radius of a hollow sphere, r = 20/2 = 10 cm

External diameter of a hollow sphere = 22 cm

External radius of a hollow sphere, R = 22/2 = 11 cm

Volume of hollow sphere,V = 4/3 π(R³ - r³)

V = 4/3 × 22/7 (11³ - 10³)

V = 88/21 (1331 - 1000)

V = 88/21 × 331

Volume of hollow sphere = 88/21 × 331 cm³

Volume of hollow sphere = 29128/21 cm³

Weight of 1 cm³ of  hollow sphere = 21g

Weight of 29128/21 cm³  of hollow sphere = 29128/21×  21 = 29128 g  

Weight of a hollow sphere = 29128/1000 kg = 29.13 kg  

[1g = 1/1000 kg]

Hence, the weight of a hollow sphere is 29.13 kg .

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Answer 2

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