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As far as I catch the question (without going digged in math), pressure doesn't go instantly from a point to a point, but has certain speed, that is sound speed. No matter if your system is opened or closed, the air is the same. If you compress air in cylinder slowly, then the air well compressible, but if you try to move the piston quickly, let's say with ...

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The term "compressible flow" is rather misleading, but unfortunately, it is what the fluid-dynamics folks have chosen to use. "Compressible flow" refers to gas flow where the temperature of the gas is significantly affected by the conversion of pressure differences to kinetic energy. Bernoulli's principle states that the work done by a pressure difference is ...

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No, the frequency will not change. If the wind is blowing at constant speed and the distance between source and observer remains constant, then the time it takes for a sound wave to get from source to observer will be constant. So the time interval between wave peaks (period T) when they are detected by the observer remains equal to the interval between ...

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You can calculate the air drag along your arms using the formula for air drag, $F = \frac{1}{2} \rho u^2 c_D A$, takin $u$ the speed at which they'll effectively move relative to air, and $A$ their projected area on the plane perpendicular to motion. $\rho$ is the density of air, that's why it's so much less efficient than in water. $c_D$ will be close to ...

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There are two reasons why the bottom hole puts out more water. 1, it is exposed for a longer period of time than the two holes above it, add, 2, the velocity of the water coming from the lowest hole in greater than the other two holes above it. See formula below: V = sq. root of 2gh where: V = velocity in ft/s g = accel const. 32.2 ft/ s^2 h = height of ...

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