Find the length of 13.2 kg of copper wire of diameter 4mm, when 1 cubic cm of copper weights 8.4 gm.

Explanation

Let the length of the wire be `h
m`
Diameter of the copper wire is `4mm`
So, radius of wire will be `(4-:2)mm`=`2mm`
Now volume of cylinder is calculated by formula `pir^2h`
Volume=`22-:7xx0.2xx0.2xxhcm^3`
Volume=`0.125hcm^3`
`0.125hxx8.4`=`13200`
h=`12500 cm`
h=`125 m`
Therefore, length of the copper wire is `125 m`.