The military jet aircraft has a gross weight of 24,000 lb and is poised for takeoff with...

The military jet aircraft has a gross weight of 24,000 lb and is poised for takeoff with brakes set while the engine is revved up to maximum power. At this condition, air with a specific weight of 0.0753 lb/ft³ is sucked into the intake ducts at the rate of 106 lb/sec with a static pressure of -0.30 lb/in.² (gage) across the duct entrance. The total cross-sectional area of both intake ducts (one on each side) is 1800 in.² The air–fuel ratio is 18, and the exhaust velocity u is 3100 ft/sec with zero back pressure (gage) across the exhaust nozzle. Compute the initial acceleration a of the aircraft upon release of the brakes.