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Ex 13.6, 2 - The inner diameter of a cylindrical wooden pipe - Ex 13.6

Ex 13.6, 2 - Chapter 13 Class 9 Surface Areas and Volumes - Part 2
Ex 13.6, 2 - Chapter 13 Class 9 Surface Areas and Volumes - Part 3

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Question 2 The inner diameter of a cylindrical wooden pipe is 24 cm and its outer diameter is 28 cm. The length of the pipe is 35 cm. Find the mass of the pipe, if 1 cm3 of wood has a mass of 0.6 g. To find mass, we have to find volume of pipe Volume of pipe = Volume of outer cylinder – Volume of inner cylinder Outer cylinder Radius of outer cylinder = r1 = (π·π‘–π‘Žπ‘šπ‘’π‘‘π‘’π‘Ÿ π‘œπ‘“ π‘œπ‘’π‘‘π‘’π‘Ÿ π‘π‘¦π‘™π‘–π‘›π‘‘π‘’π‘Ÿ)/2 = 28/2 = 14 cm Height of outer cylinder = h = 35 cm Volume of outer cylinder = πœ‹π‘Ÿ12β„Ž = πœ‹(14)2(35) Inner Cylinder Radius of inner cylinder = (π·π‘–π‘Žπ‘šπ‘’π‘‘π‘’π‘Ÿ π‘œπ‘“ π‘–π‘›π‘›π‘’π‘Ÿ π‘π‘¦π‘™π‘–π‘›π‘‘π‘’π‘Ÿ)/2 = r2 = 24/2 = 12 cm Height of inner cylinder = h = 35 cm Volume of inner cylinder = πœ‹π‘Ÿ22β„Ž = πœ‹(12)2(35) Now, Volume of pipe = Volume of outer cylinder – Volume of inner Volume of pipe = πœ‹(14)2(35) – πœ‹(12)2(35) = πœ‹(35)( (14)2βˆ’(12)2) = 22/7Γ—(35)Γ—( 14 βˆ’12)(14+12) = 22 Γ— 5 Γ— 2 Γ— 26 = 5720 cm3 Now it is given that Mass of 1 cm3 volume = 0.6 g ∴ Mass of 5720 cm3 volume = (5720 Γ— 0.6) g = ((5720Γ—0.6)/1000) kg = 3.432 kg. Therefore, mass of pipe is 3.432 kg

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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.