If V₁ is the jet velocity and V₀ is the vehicle velocity, then the propulsive efficiency of a rocket is given by

[2(V₀/V₁)]/ [1 + (V₀/V₁)²]

(V₀/V₁)/ [1 + (V₀/V₁)²]

V₀/(V₀ + V₁)

V₁/(V₀ + V₁)

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