Question

A piece of ductile metal is n the form of a cylinder of diameter 1 cm and length 11 cm.it is drawn out into a wire of diameter 1 mm.What will be the length if the wire obtained?

Answer 1

volume of cylinder =volume of wire
πR²h=πr²H
$( \frac{1}{2} )^{2}$x11=$( \frac{1}{10x2} ) ^{2}$h
$\frac{11}{4}$ x4x100=h
1100cm=h
1.1km=h

Answer 2

given : diameter of cylinder is 1cm,
            its length is 11cm
            diameter of wire is 1mm

To find : length of wire 

Solution;

we have diameter of cylinder is 1cm 
∴ radius of cylinder is 1/2 cm

also diameter of wire is 1mm
∴ radius of wire is 1/2 mm 
   = 5/100 cm

∵ the metal is drawn in wire 
∴ volume of metal = volume of wire
⇒ pi r1² h1 = pi r2² h2
⇒ 1/2 * 1/2 * 11 = 5/100 * 5/100 * h2
⇒ h2 = 1100 cm

∴length of wire is 1100 cm