Propulsive efficiency condition for a rocket A rocket achieves maximum overall propulsive efficiency when the aircraft (vehicle) flight speed is how related to the jet exhaust velocity? Choose the correct option.
Mechanical Engineering
Compressors, Gas Dynamics and Gas Turbines
Difficulty: Easy
Choose an option
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AEqual to the jet velocity
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BHalf of the jet velocity
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CDouble the jet velocity
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DMuch less than the jet velocity
Answer
Correct Answer: Equal to the jet velocity
Explanation
Concept/ApproachPropulsive efficiency depends on the velocity match between the vehicle and the exhaust. For momentum devices (including rockets), efficiency is maximized when flight speed ≈ jet speed, minimizing kinetic energy wasted in the exhaust slipstream.
Final AnswerEqual to the jet velocity