To calculate the density of the cube, we can use the formula:
\[ \text{Density} = \frac{\text{Mass}}{\text{Volume}} \]
First, we calculate the volume of the cube. The volume \( V \) of a cube with side length \( s \) is given by:
\[ V = s^3 \]
For a cube with a side length of 2 meters:
\[ V = 2^3 = 8 , \text{m}^3 \]
Now, we can substitute the mass and the volume into the density formula. The mass of the cube is given as 40 kg.
\[ \text{Density} = \frac{40 , \text{kg}}{8 , \text{m}^3} = 5 , \text{kg/m}^3 \]
Therefore, the density of the cube is 5 kg/m³.