A jet airliner is cruising at a speed of 900 km/h with each of its three engines discharging air with a velocity of 800 m/s relative to the plane. Determine the speed of the airliner after it has lost the use of (a) one of its engines. (b) two of its engines. Assume that the drag due to air friction is proportional to the square of the speed and that the remaining engines keep operating at the same rate.
(a)
The speed of the air-liner after it has lost the use of one of its engine.
Answer to Problem 14.75P
Speed
Explanation of Solution
Given information:
Cruising speed
Discharge relative velocity
Thrust formula for engine is,
And drag force
When all the three engine working the cruising speed is
Calculation:
When one engine fails two are working then,
Cruising speed =
By solving the above equation we get,
(b)
The speed of the air-liner two of its engine fails.
Answer to Problem 14.75P
Speed
Explanation of Solution
Given information:
Cruising speed
Discharge relative velocity
Thrust formula for engine is,
And drag force
When all the three engine working the cruising speed is
Calculation:
When two of its engine fails then only one is working then,
Cruising speed
By solving the above equation we get,
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Chapter 14 Solutions
Vector Mechanics For Engineers
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