Gas flows at a steady rate in a 120-mm-diameter pipe that enlarges to a 180-mm-diameter pipe. At a certain section of the 120-mm pipe the density of the gas is 165 kg/m^3 and the velocity is 15 m/s. At a certain section of the 180-mm pipe the velocity is 10 m/s. What must be the density of the gas at that section? If these same data were given for the case of unsteady flow at a certain instant, could the problem be solved? Discuss.