Find the length of 13.2 kg of copper wire of diameter 4 mm, when 1 cub

1.	Find the length of 13.2 kg of copper wire of diameter 4 mm, when 1 cubic cm of copper weighs 8.4 gm.
Answer» We have, Weight of copper wire = 13.2 kg = 13200 gm Diameter of wire = 4 mm Radius of wire = d/2 = 4/2 = 2mm = 0.2cm Let length of wire be ‘h’ cm So, Weight (Density) of 1 cubic cm wire = 8.4 gm We know, volume = weight/density Volume × density = weight πr²h × 8.4 = 13200 22/7 × 0.2 × 0.2 × h × 8.4 = 13200 h = 13200×7 / 22×0.2×0.2×8.4 = 92400/7.392 = 12500 cm = 125m ∴ Length of 13.2kg of copper wire is 125 m.

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

Answer»

We have,

Weight of copper wire = 13.2 kg = 13200 gm

Diameter of wire = 4 mm

Radius of wire = d/2 = 4/2 = 2mm = 0.2cm

Let length of wire be ‘h’ cm

So,

Weight (Density) of 1 cubic cm wire = 8.4 gm

We know, volume = weight/density

Volume × density = weight

πr²h × 8.4 = 13200

22/7 × 0.2 × 0.2 × h × 8.4 = 13200

h = 13200×7 / 22×0.2×0.2×8.4

= 92400/7.392

= 12500 cm = 125m

∴ Length of 13.2kg of copper wire is 125 m.