Air is heated as it flows subsonically through a duct. when the amount of heat transfer reaches 67 kj/kg, the flow is observed to be choked and the velocity and the static pressure are measured to be 680 m/s and 261 kpa. disregarding frictional losses, determine the velocity, static temperature, and static pressure at the duct inlet. take the properties of air to be k = 1.4, cp = 1.005 kj/kg·k, and r = 0.287 kj/kg·k.