Question

2.2 cubic dm of brass is to b drawn into a cylindrical wire 0.25 cm in diameter . find the length of the wire.

Answer 1

Solution:-

Let the length of the wire be 'h' cm
Volume of metal = 2.2 dm³ = 2.2(10)³
= 2.2*1000 = 2200 cm³   (As 1 dm = 10 cm)
Given : Diameter = 0.25 cm
So, radius = 0.25/2 = 0.125 cm
Volume of metal in the wire = 2200 cm³
∴ πr²h = 2200
⇒ 22/7*(0.125)²*h = 2200
⇒ h = (2200*7)/(22*0.125*0.125)
⇒ h = 15400/0.34375
⇒ h = 44800 cm or 44800/10 
h = 4480 dm
Answer.

Answer 2

Answer:

The length of the wire is 448 m .

SOLUTION :  

Let the length of the wire be 'h' cm

Given : Volume of metal (brass) = 2.2 dm³ = (2.2 × 10³) cm³ = 2200 cm³

[1 dm³ = 10³ cm]

Volume of metal(brass) = 2200 cm³

Diameter of cylindrical wire , d = 0.25 cm

Radius of the cylindrical wire, r = 0.25/2 = 0.125 cm

Since the metal ( brass) is converted into cylindrical wire, so  

Volume of cylindrical wire = Volume of metal (brass) in the wire

πr²h = 2200 cm³

22/7× (0.125)²× h = 2200

0.125 × 0.125 × 22 × h = 2200 × 7

h = (2200 × 7)/ (22 × 0.015625)

h = 15400/0.34375

h = 44800 cm

h = 44800/100  

[1 cm = 1/100 m ]

h = 448 m

Hence, the length of the wire is 448 m .

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