A 156-kg coil of sheet steel is 0.80 mm thick and 50 cm wide. How long is the steel in the coil?

Answer 1

The volume of the steel in the coil is
V = Length*Width*Thickness
= (mass)/(density)

= 156 kg/7.9*10^3 kg/m^3
= 1.98*10^-2 m^3

Length = 1.98*10^-2/(0.5)(8*10^-4)
= 49.4 meters

I have used an "average" density for steel. If you know the alloy type, you can find a more accurate value.