The jet is traveling at a speed of 500mi/h, 30° with the horizontal. If the fuel is bein...

The jet is traveling at a speed of 500mi/h, 30° with the horizontal. If the fuel is being spent at 3 lb/s, and the engine takes in air at 400 lb/s, whereas the exhaust gas (air and fuel) has a relative speed of 32 800 ft/s, determine the acceleration of the plane at this instant. The drag resistance of the air is FD = (0.7 v2) lb, where the speed is measured in ft/s. The jet has a weight of 15 000 lb. Hint: See Prob.

Prob:

The 12-Mg jet airplane has a constant speed of 950 km/h when it is flying along a horizontal straight line. Air enters the intake scoops S at the rate of 50 m3/s. If the engine burns fuel at the rate of 0.4 kg/s and the gas (air and fuel) is exhausted relative to the plane with a speed of 450 m/s, determine the resultant drag force exerted on the plane by air resistance. Assume that air has a constant density of 1.22 kg/m3. Hint: Since mass both enters and exits the plane, Eqs. 15-28 and 15-29 must be combined to yield