From which substance is a rectangular rod with a mass of m = 78 g made, if its length is l = 0.5 cm

From which substance is a rectangular rod with a mass of m = 78 g made, if its length is l = 0.5 cm, width b = 2.0 cm, height h = 1.0 dm?

In order to solve the problem, you need to find the density of the substance. Density formula:

ρ = m / V

The mass of the bar is known. Let’s find its volume:

V = 0.5 cm × 2 cm × 10 cm = 10 cm3

Let’s translate all the data into the SI system:

m = 78 g = 0.078 kg

V = 10 cm3 = 0.00001 m3

Let’s calculate the density of the substance from which the rod is made:

ρ = 0.078 kg / 0.00001 m3 = 78 / 0.01 = 7800 kg / m3

Next, you need to compare the resulting number with the known densities of substances using the density table. The density of 7800 kg / m3 is closest to iron.