Question

A copper wire (density=8.96 g/cm^3) has a diameter of 0.25 mm. If a sample of this copper wire has a mass of 22 g, how long is the wire?

Answer 1

0.25 mm * 1 cm/10 mm = 0.025 cm
so
r = 0.0125 cm
Area = pi r^2 = 4.91*10^-4 cm^2
volume = Area * x = 4.91*10^-4 x cm^3
so
8.96 g/cm^3* 4.91*10^-4 x cm^3 = 22 g

x = 5002 cm
= 50 meters