Calculation example

1.A solid metal bar has a mass of 400g and a volume of 0.5m³. Calculate the density of the  metal bar.

Convert 400g to kg, so this is 0.4kg

Density = mass/volume

Density = 0.4/0.5 = 0.8 kg/m³

2.Calculate the volume of a gold bar which has a mass of 2000kg and a density of 19300 kg/m³.

Volume = mass/density

Volume = 2000/19300 = 0.104m³

3. Concrete has a density of 2200kg/m³. Use the diagram below to answer the following question.

The concrete slab above  has a mass of 4.6kg and is a  cuboid shape with a length of 0.4m and width of 0.4m. Calculate the thickness of the concrete slab.

Density = mass/volume

Volume = mass/density

Volume = 4.6/2300 = 2 x 10^-3 m³

Volume = length x width x thickness

2 x 10^-3 = 0.4 x 0.4 x thickness

Thickness = 2 x 10^-3/(0.4 x 0.4) = 0.0125m

Thickness = 0.0125m, or 1.25cm