A bucket of water is pulled up in humid air

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In summary, the problem poses the question of how much additional force is required to pull a bucket filled with water through a cloud of water droplets, assuming the air has zero viscosity and is massless. The relevant equation, Newton's second law, is listed with a typo and the attempted solution contains an equation that does not follow from it. The problem also lacks specific details, such as the exact question to be answered.
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Karol
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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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  • #2
Can a bucket that is full of water accumulate any more water?
 
  • #3
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.
 

Related to A bucket of water is pulled up in humid air

What is the meaning of "a bucket of water is pulled up in humid air"?

The phrase "a bucket of water is pulled up in humid air" refers to the process of lifting a bucket filled with water from a body of water or other source, while the surrounding air is humid.

How does humidity affect the weight of a bucket of water?

Humidity does not directly affect the weight of a bucket of water. However, it can indirectly affect the weight by changing the density of the air. Humid air is less dense than dry air, so it exerts less pressure on the surface of the water in the bucket. This can make it easier to pull the bucket up through the air.

Does the temperature of the air impact the process of pulling up a bucket of water?

Yes, the temperature of the air can impact the process of pulling up a bucket of water in humid air. As the temperature of the air increases, the water molecules in the air become more active and can hold more water vapor. This can lead to higher humidity levels, making the air less dense and potentially easier to pull the bucket up through.

Why is it more difficult to pull up a bucket of water in dry air compared to humid air?

In dry air, the water molecules in the air are less active and can hold less water vapor. This makes the air more dense and creates more resistance when trying to pull up a bucket of water. Additionally, dry air can also cause evaporation from the surface of the water, making it lighter and more difficult to lift.

Is there a limit to how high the bucket of water can be pulled in humid air?

There is no specific limit to how high a bucket of water can be pulled in humid air. However, as the bucket is pulled higher, the air pressure decreases and the water in the bucket may start to evaporate, making it lighter and potentially more difficult to lift. Other factors such as the weight and strength of the person pulling the bucket and the weight and size of the bucket itself can also impact how high it can be pulled.

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