Q. 334.7( 23 Votes )
A copper wire of diameter 6 mm is evenly wrapped on a cylinder of length 18 cm and diameter 49 cm to cover its whole surface. Find the length and the volume of the wire. If the density of copper be 8.8 g per cu-cm, find the weight of the wire.
Answer :
Given,
Diameter of the copper wire = 6 mm = 0.6 cm
Radius of the copper wire = 0.3 cm
Length of the cylinder = 18 cm
Diameter of the cylinder = 49 cm
Radius of the cylinder = 
cm
Density of the copper = 8.8g
Number of the rotations on the cylinder = 
= 30 cm
Base circumference of the cylinder = 2πr = 
= 154 cm
So,
Length of the wire = 154 × 30 = 4620 cm
Volume of the wire = πr2h
= 
× 0.3 × 0.3 × 4620 = 1306.8
Weight of the wire = volume × density
= 1306.8 × 8.8 = 11,499.84 gm
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