the picture attached resembles a lawn sprinkler but it works on air not water.(adsbygoogle = window.adsbygoogle || []).push({});

what i am trying to find is

1. if P> Pa where Pa is the atmospheric pressure, does the rotor turn and, if so, in which direction?

2. if P< Pa where Pa is defined as above, does the rotor turn and, if so, which direction.

for 1 i am pretty sure about which way it turns but i have been unable to come up with a substantial reason as to why it turns in that direction. i tried 2 explanations which werent satisfactory, namely stating newtons 3rd law and tried using the rocket equation(?) to explain its movement (ie m dv + u dm = 0) where u is the effective exhaust velocity. i also suggested that the kink in the sprinkler being the part that makes it turn but couldnt explain why

can anyone come up with a "sufficient" argument to explain the movement of the rotor for both parts 1 and 2?

i think it mat have something to do with conservation of angular momentum but i am not sure about the details

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# Which way did it go?

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