Answer:
304(pi) g
Explanation:
First we find the volume of the hollow ball. Then we find the mass using the volume and density.
Let R = exterior radius = 3 cm
Let r = interior radius = 2 cm
volume = exterior volume - interior volume
volume = (4/3)(pi)R^3 - (4/3)(pi)r^3
volume = (4/3)(pi)(R^3 - r^3)
volume = (4/3)(pi)(3^3 - 2^3) cm^3
volume = (4/3)(pi)(27 - 8) cm^3
volume = (76/3)pi cm^3
Now we use the density and the volume to find the mass.
density = mass/volume
mass = density * volume
mass = 12 g/cm^3 * (76/3)pi cm^3
mass = 304(pi) g
Answer: 304(pi) g