A 50km horizontal commercial steel pipe of ID 61 cm is used to transport methane. The upstream and downstream pressures are kept constant at 490 kPa and 70 kPa respectively. The conditions are such that isothermal flow can be assumed. Methane is at 15 o C and its viscosity is 0.011 cP. Methane behaves ideally at these conditions. a) Calculate the flow rate (kg/s) b) If = 1.31 for methane, is the flow subsonic, sonic or supersonic Hint: assume a value of f = 0.0025 and check to see if the assumption is reasonable. Refer to E balance given in Question 1