Solve this multiple-choice question and choose the correct option.

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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.

Difficulty: Easy

Equal to the jet velocity
Half of the jet velocity
Double the jet velocity
Much less than the jet velocity

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

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