The inner diameter of a cast-iron hollow ball is 8 cm, and its outer diameter is 10 cm.

The inner diameter of a cast-iron hollow ball is 8 cm, and its outer diameter is 10 cm. Determine the mass of the ball if the density is 7.3 cm ^ 3

It is necessary to find the volume of metal:
Vm = V-Vv
Let’s define the volume of the ball:
V = 4 * π * R³ / 3 = 4 * 3.14 * 1000/3 = 4188 cm³.
Determine the volume of the internal void:
Vw = 4 * π * r³ / 3 = 4 * 3.14 * 512/3 = 2144 cm³.
Determine the volume of the metal:
Vm = V-Vv = 4188-2144 = 2044 cm³.
To calculate the mass, we will use the formula from physics:
m = ρ * Vm
Substituting the numbers we get:
m = ρ * Vm = 7.3 * 2044 = 14921 g.
Answer: the mass of the ball is 14921 g or 15 kg.