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Ex 13.8, 3 - The diameter of a metallic ball is 4.2 cm - Ex 13.8

Ex 13.8, 3 - Chapter 13 Class 9 Surface Areas and Volumes - Part 2

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Ex 11.4,3 The diameter of a metallic ball is 4.2 cm. What is the mass of the ball, if the density of the metal is 8.9 g per cm3? To find mass, we have to find volume of sphere Radius of sphere = r = π·π‘–π‘Žπ‘šπ‘’π‘‘π‘’π‘Ÿ/2 = 4.2/2 = 2.1 cm Now, volume of the sphere = 4/3 Ο€r3 = 4/3 Γ— 22/7 Γ— 2.1 Γ— 2.1 Γ— 2.1 cm3 = 38.808 cm3 Now, Density = π‘€π‘Žπ‘ π‘ /π‘‰π‘œπ‘™π‘’π‘šπ‘’ 8.9 = π‘€π‘Žπ‘ π‘ /38.808 π‘€π‘Žπ‘ π‘ /38.808 = 8.9 Mass = (38.808 Γ— 8.9) g Mass = 345.3912 g. Mass = 345.39g (approx) Therefore, mass of metallic ball is is 345.39g (approx)

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.