M.L Aggarwal book Important Question of class 10 chapter Based on Mensuration for ICSE BOARD.
A cylindrical roller made of iron is 2 m long. Its inner diameter and the thickness is given .
Find the weight of the roller in kg, if 1 cm3 of iron weighs 8 g.
This is the Question Number 22, Exercise 17.1 of M.L Aggarwal.
Deepak BoraNewbie
A cylindrical roller made of iron is 2 m long. Its inner diameter is 35 cm and the thickness is 7 cm all round. Find the weight of the roller in kg, if 1 cm3 of iron weighs 8 g.
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Length of the roller, h = 2 m = 200 cm [1m = 100 cm]
Inner diameter = 35 cm
Inner radius, r = 35/2 cm
Thickness = 7 cm
Outer radius, R = (35/2)+7
= (35+14)/2
= 49/2 cm
Volume of the iron in roller = π(R2-r2)h
= (22/7)[( 49/2)2-(35/2)2]200
= (22/7)[( 492-352/4]200
= (22/7)×50( 492-352)
= (22/7)×50( 492-352)
= (22/7)×50 (2401-1225)
= (22/7)×50×1176
= 184800 cm3
Given 1 cm³ of iron weighs 8 g.
Weight of the roller = 184800×8 = 1478400 g
= 1478.4 kg [1 kg = 1000 g]
Hence the weight of the roller is 1478.4 kg.