Practice: A copper wire (density = 8.96 g/cm^{3}) has a diameter of 0.32 mm. If a sample of this copper wire has a mass of 21.7 g, how long is the wire?

The **D****ensity of geometric objects** generally includes spheres, cubes and cylinders.

Concept #1: When given the mass of a geometric object you can relate it to its volume and density.

Example #1: The density of silver is 10.5 g/cm^{3}. What is the mass (in kilograms) of a cube of silver that measures 0.56 m on each side?

Practice: A copper wire (density = 8.96 g/cm^{3}) has a diameter of 0.32 mm. If a sample of this copper wire has a mass of 21.7 g, how long is the wire?

Practice: If the density of a certain spherical atomic nucleus is 1.0 x 10^{14} g/cm^{3} and its mass is 3.5 x 10^{-23} g, what is the radius in angstroms? (Å= 10^{−10} m)