One kg of air undergoes a power cycle consisting of the following processes: Constant volume from p_1 = 138 kPa, T_1 = 278 K to T_2 - 455.6 K Adiabatic expansion to v_2 = 1.4v_3 Constant-pressure compression Sketch the cycle on a p-v diagram. Assuming ideal gas behavior, determine the pressure at state 2, in kPa. the temperature at state 3, in K. the thermal efficiency of the cycle.