• # question_answer        The effective jet exit velocity from a rocket is 2700 m/s. The forward flight velocity is 1350 m/s. the propulsive efficiency of the unit is:         A) 200%               B) 100%        C) 66.666%                       D) 33.333%

Propulsive efficiency, ${{\eta }_{p}}=\frac{2\,{{v}_{f}}}{{{v}_{g}}+{{v}_{f}}}=\frac{2\times 1350}{2700+1350}=\frac{2}{3}=66.666%$