A cylinder rod formed from silicon is 16.8 cm long and has a mass of 2.17 kg. The density of silicon is 2.33 g/cm3. What is the diameter of the cylinder?

We are given the length, the mass and the density of the cylinder. First let us calculate for the volume by dividing the mass by the density.

volume = mass / density

where mass = 2.17 kg = 2170 g, therefore:

volume = 2170 g / (2.33 g/cm^3)

volume = 931.33 cm^3

We know that the volume of a cylinder has the formula:

volume = π r^2 h

since h = 16.8 cm, therefore calculating for radius:

931.33 cm^3 = π r^2 (16.8 cm)

r^2 = 17.646 cm^2

r = 4.2 cm

Hence the diameter (d) is:

d = 2 r

d = 8.4 cm