Final answer:
Jack's rock has a density of 2 g/cm^3. This is calculated by dividing the mass of 6g by the volume of 3cm^3. The density of the rock is lower than typical granite.
Step-by-step explanation:
The given rock has a mass of 6g and a volume of 3cm3. To find the density of the rock, we use the formula D = m/V where 'D' is density, 'm' is mass, and 'V' is volume. So the density of Jack's rock is D = 6g / 3cm3 = 2 g/cm3.
In comparison to familiar materials, the density of granite ranges approximately from 2.65 g/cm3 to 2.75 g/cm3. Consequently, Jack's rock has a lower density than typical granite, which might indicate that it is not granite or contains impurities or air pockets.