A cylindical tube opened at both the ends is made of iron sheet which is 2 cm thick. If the outer diameter is 16 cm and its length is 100 cm, find how many cubic centimetres of iron has been used in making the tube ?

Explanation

Given,outer diamter of a cylinder tube, d= 16 cm
`rArr " " r_(1)`= outer radius of a cylindrical tube, 8 cm" "`[because d = 16 cm]`
`r_(2)` = inner radius of a cylindrical tube = (`r_(1)`- thickness of the iron sheet)
`= 8-2= 6 cm`
and height of a cylindrical tube, h = 100 cm
Volume of metal used in making cylindrical tube
= Outer volume of a cylindeer tube - Inner volume
`= (22)/(7) xx 100(8^(2) - 6^(2))`
`= (22)/(7) xx 100 (8+6) (8-6)`
`= (22)/(7) xx 100 xx 14 xx2`
`= 2200 xx 4 = 8800 cm^(3)`
Hence, `8800 cm^(3)` of iron has been used in making a cylinder tube .