The copper ball has a mass of 6 kg and a volume of 2 dm3. Is this ball solid or hollow?

Given:
m = 6 kilograms is the mass of the copper ball;
V = 2 dm3 (cubic decimeters) – the volume of the copper ball;
ro = 8900 kg / m3 (kilogram per cubic meter) – copper density.
It is required to determine whether a solid ball or it has cavities.
Let’s convert the units of measurement of volume to the SI system:
V = 2 dm3 = 2 * 10-3 m3 (cubic meters).
Let us determine the volume of a copper ball of mass m that it would occupy if there were no cavities in it:
V1 = m / ro = 6/8900 = 0.00067 m3 = 6.7 * 10-4 m3.
Since V> V1 (2 * 10-3> 6.7 * 10-4), there are cavities in the copper ball.
Answer: There are cavities in the copper ball.