(Ill) Thrust o f a rocket, (a) Use Bernoullis equation

Chapter , Problem 61

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(Ill) Thrust o f a rocket, (a) Use Bernoullis equation andthe equation of continuity to show that the emission speedof the propelling gases of a rocket isv = V t iP - -Po)/p,where p is the density of the gas, P is the pressure of the gasinside the rocket, and Zq is atmospheric pressure just outsidethe exit orifice. Assume that the gas density stays approximatelyconstant, and that the area of the exit orifice, A 0, ismuch smaller than the cross-sectional area, A, of the insideof the rocket (take it to be a large cylinder). Assume alsothat the gas speed is not so high that significant turbulenceor nonsteady flow sets in. (b) Show that the thrust force onthe rocket due to the emitted gases isF = 2A0{P - P0).