if 1 cubic cm of cast iron weighs 21 gms then..., Area & Volume, General Mathematics

Question:If `1` cubic cm of cast iron weighs `21 gms, then the weight of a cast iron pipe of lenght `1` metre `1` metre with a bore of `3` cm and in which the thickness of the metal is `1` cm, is :

A `1.6 kg` 
B `21 kg` 
C `24.2 kg` 
D `26.4 kg`

/113

+ AnswerD

+ ExplanationInner radius`= 1.5,` outer radius`= 2.5 cm.`

:. Volume of iron

`= [π xx (2.5)^2 xx 100 - π xx (1.5)^2 xx 100] cm^3`

`= 22/7 xx 100 xx [(2.5)^2 - (1/5)^2] cm^3`

`= (8800/7) cm^3`

:. Weight of iron

`= (8800/7 xx 21/1000) kg`

`= 26.4 kg.`

+ Report

Descriptive on Area & Volume Ebook

Total Preview: 1127