There is a hollow copper ball with a mass of 178g and a volume of 30cm3. If the hollow part is filled with water, what is the mass of the whole copper ball? (the known density of copper is 8.9 × 103kg / m3)

There is a hollow copper ball with a mass of 178g and a volume of 30cm3. If the hollow part is filled with water, what is the mass of the whole copper ball? (the known density of copper is 8.9 × 103kg / m3)


Volume of copper in hollow copper ball v = m / P copper = 178g / (8.9g / cm ^ 3) = 20cm ^ 3
Volume of hollow part V '= total volume - v = 30-20 = 10cm ^ 3
The mass of water filled in the hollow part M '= pwater * V' = (1g / cm ^ 3) * 10cm ^ 3 = 10g
Total mass m = 178 + 10 = 188g