A bucket of water is pulled up in humid air

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SUMMARY

The discussion centers on the physics of a bucket filled with water being pulled upwards through humid air, specifically analyzing the forces at play. The relevant equation derived is F = 2ρAv₀², which accounts for the interaction between the bucket and water droplets in the air. The problem highlights the need for clarity regarding the forces involved, particularly in relation to gravity and the behavior of water droplets. A critical typo in the relevant equation was noted, emphasizing the importance of accuracy in problem-solving.

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  • Newton's Second Law of Motion
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  • Basic mechanics of forces acting on objects
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  • Research the behavior of water droplets in humid air
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Homework Statement


A bucket with surface A, full of water, is pulled upwards through humid air, humidity ρ[mass/unit volume], at constant speed v0. the cloud is at rest and the drops instantly stop at hitting the water.

Homework Equations


Newton's second law: ##F=\frac{d(ma)}{dt}=\dot m v+m\dot v##

The Attempt at a Solution


The bucket that collects water isn't an isolated system, so:
$$F=\dot m v_0+\dot v m+\Delta P=\dot m v_0+0+\rho A v_0^2=2\rho A v_0^2$$
 
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Can a bucket that is full of water accumulate any more water?
 
The problem as posed leaves much to the imagination. Among the things left unspecified is the question that is to be answered.

At a guess, we are expected to imagine the air as a cloud of water droplets. The air has zero viscosity and is massless. The suspended water droplets merge with the bucket as the bucket's top surface is pulled through their location. The question is what force (beyond that required to support the bucket against gravity) is required due to the interaction with the water droplets.

The "Relevant equation" listed in of the OP includes a typo.
The "attempt at a solution" contains an equation that does not follow from the relevant equation.
 

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