Final answer:
The object will float in water because its density is less than the density of water.
Step-by-step explanation:
The object will float in water because its density is less than the density of water. Density is calculated by dividing the mass of an object by its volume. In this case, the mass of the object is 18g and its volume is 9 cm³. To find the density, we divide 18g by 9 cm³, which gives us a density of 2 g/cm³.
Since the density of water is approximately 1 g/cm³, and the density of the object is greater than the density of water, the object will float in water.