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I understand that the force with which a water rocket is accelerated is equal to the force of the reaction mass (or water) sent in the other direction.

If the change in mass of the water as it is being ejected can be calculated from this equation:

change of M = area of exit x water density x (velocity of water x time)

How am I supposed to find out the change of mass if I have no idea what the velocity and time is?

Do I have to compare that with the velocity of the rocket (which I know)?

Thanks

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# Homework Help: Water rocket force

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