Final answer:
The density of the cube is 2.5 kg/m³. The cube will float in fresh water.
Step-by-step explanation:
To work out the density of the cube, we can use the formula: density = mass/volume. Since the cube has sides of 2 meters, its volume would be 2 x 2 x 2 = 8 cubic meters. The mass of the cube is given as 20,000 g which is equivalent to 20 kg. Therefore, the density of the cube is 20 kg / 8 cubic meters = 2.5 kg/m³.
To determine if the cube will float in fresh water, we compare its density to the density of fresh water, which is 1000 kg/m³. Since the density of the cube is less than the density of fresh water, the cube will float in fresh water.