Question:
2.2 cubic dm of brass is to be drawn into a cylindrical wire 0.25 cm in diameter. Find the length of the wire.
Solution:
Let r cm be the radius of the wire and h cm be the length of the wire.
Volume of brass = Volume of the wire
We know that the volume of brass = 2.2 dm3= 2200 cm3
Volume of the wire= πr2h = (0.125 cm)2 (h)
$h=\frac{2200 \mathrm{~cm}^{3}}{\pi(0.125 \mathrm{~cm})^{2}}=44800 \mathrm{~cm}=448 \mathrm{~m}$
Thus, length of the wire is 448 m.