(D)An oil pipeline and a 1.3-m' rigid air tank are connected to each other by a manometer, as shown in the Figure below. If the tank contains 15 kg of air at 80C, determine: the absolute pressure in the pipeline and the change in Ah when the temperature in the tank drops to 20C. Assume the pressure in the oil pipeline to remain constant, and the air volume in the manometer to be negligible relative to the volume of the tank. Oil SG = 2.68 1.3 m Air. 80C h = 75 cm Ah = 20 cm 3D D=4 mm Mercury SG = 13.6 50 FIGURE P3-149