First, we need to find the radius of the cone. The radius of the cone is equal to half the diameter of the hemisphere, so it is equal to the radius of the hemisphere.
Since the height of the cone is equal to the diameter of the hemisphere, we have a right triangle with the radius, height, and diameter of the cone. From the Pythagorean theorem, we can find the radius of the cone:
r² + h² = d²
r² + 12² = 2r²
12² = r²
Once we have the radius of the cone, we can find the volume of the cone using the formula for the volume of a cone:
V = (1/3) * π * r² * h
V = (1/3) * π * 12² * 12
V = (1/3) * π * 144 * 12
V = 576π
Finally, to find the total volume of the object, we sum the volume of the cone with the volume of the hemisphere:
V_total = V_cone + V_hemisphere
V_total = 12 + (2/3) * π * r³
V_total = 12 + (2/3) * π * (12)³
V_total = 12 + (2/3) * π * 1728
V_total = 12 + 1152π
Therefore, the volume of the whole object composed of the hemisphere and the cone is 12 + 1152π m³, or approximately 3635.4 m³.