A cube is placed in a pool of water. If the cube is 12 cm long on each side, what is the weight of the cube? (Use 1000 kg/m3 for the density of water)

Answer 1

The answer begins with the formula for the mass which will be

total mass of the water = (mass density of water) x (Volume of the water)

m_total = ρ_waterV_water

The density is a characteristic of the substance of which the object (the water contained within the cube) is composed. (By the way, the density will depend on the temperature as well as the phase of the matter (liquid, solid, gas) but that's a topic for another time).

The volume of a cube whose sides are s in length will be s³

Now to complete the calculation, keep in mind that the sides are given in terms of cm, whereas the density is given in terms of kg/m³., so one can either the side length to meters (12 cm = 0.12 m) OR the density to kg/cm³.

Either way the solution will (or should) be 1.7 kg. (adhering to significant figures)