3. In an air pipeline, the flow has the following conditions at section 1: 25C, 1.8 bar, 15m/s velocity, and 50mm inside diameter of pipe. At section 2 the conditions are : 25C, 1.3 bar, 75mm inside diameter of pipe. Calculate the mass flow rate of air, and the velocity at section 2. At 25C and 1.8 bar pressure, air has a density of 2.kg/m3