# Water flowing in and out of a bucket

• Pinkk
In summary, the conversation discusses a cylindrical bucket being filled with water and the calculation of the height at which the water stops rising due to leakage from a small hole at the bottom of the bucket. The equations of A1v1 = A2v2 and Bernoulli's equation are suggested as possible methods for solving the problem. The concept of equal pressure at the top and bottom of the bucket and the use of potential energy are also mentioned as factors in determining the height. The solution involves finding the volume of inflow and using Bernoulli's equation to calculate the height at which the water stops rising.
Pinkk

## Homework Statement

A cylindrical bucket is being filled with water at the rate of 2 * 10^(-3) m^3/s. The bucket itself is od diameter 1.5 m and height 2.5 m. The bucket has a small circular hole at the bottom, with diameter 3 cm. Therefore even as the bucket is being filled, there is a leakage from the bottom. At first, the water rises in the bucket. Eventually, the water stops rising when it reaches a height of h. At this point the leakage from the bottom of the bucket equals the water intake from the tap. Find this height h.

## Homework Equations

I am not sure, we barely covered this in my class. I'm guessing A1v1 = A2v2 and Bernoulli's equation come into play somehow.

## The Attempt at a Solution

I really haven't attempted it because as I stated we did really go over this so much in my class.

Thanks!

The level of water in the bucket will stop rising when the volume of inflow is equal to A2V2.
Volume of inflow and A2 is known. Find V2.
The pressure on the top and bottom of the bucket is the same i.e. atmospheric pressure.
At the opening at the bottom V1 is almost zero. Potential energy with respect to the bottom of the bucket is ρgh. Using Bernoulli equation find h.

I would approach this problem by first identifying the key variables and equations involved. In this case, we have the rate of water intake from the tap (2 * 10^(-3) m^3/s), the dimensions of the bucket (diameter = 1.5 m, height = 2.5 m), and the diameter of the hole at the bottom (3 cm). We can use the equation A1v1 = A2v2 (where A is the cross-sectional area and v is the velocity) to relate the intake velocity at the top of the bucket to the outflow velocity through the hole at the bottom.

Next, we can use Bernoulli's equation, which relates the pressure, velocity, and height of a fluid in a closed system, to determine the height of the water in the bucket when the inflow and outflow rates are equal. This can be represented by the equation P1 + 1/2ρv1^2 + ρgh1 = P2 + 1/2ρv2^2 + ρgh2, where P is the pressure, ρ is the density of the fluid, v is the velocity, and h is the height.

By setting P1 = P2 (since the bucket is open to the atmosphere), v1 = 0 (since the water is not flowing out of the top of the bucket), and v2 = A1v1/A2 (from A1v1 = A2v2), we can simplify Bernoulli's equation to ρgh1 = 1/2ρ(A1/A2)^2v1^2, and solve for h1 (the height of the water in the bucket).

Substituting in the given values, we get h1 = (1/2)(0.03/0.0075)^2(2 * 10^(-3)) = 0.08 m. Therefore, the height of the water in the bucket when the inflow and outflow rates are equal is approximately 8 cm.

I would also mention that this solution assumes laminar flow (smooth and orderly) through the hole, and is a simplified version of the problem since it neglects factors such as surface tension and turbulence. Further analysis and experimentation may be needed to account for these factors and obtain a more accurate solution.

## 1. How does water flow in and out of a bucket?

Water flows in and out of a bucket due to the force of gravity. When the bucket is filled with water, the weight of the water creates pressure that pushes it out of the bucket. When the bucket is flipped over, gravity pulls the water downward and out of the bucket.

## 2. Why does water stop flowing out of a bucket when it is flipped over?

When a bucket is flipped over, air enters the bucket through the opening and disrupts the flow of water. This creates an air pocket that prevents the water from flowing out smoothly. Additionally, the angle at which the bucket is flipped can also affect the flow of water.

## 3. What factors affect the flow of water in and out of a bucket?

The flow of water in and out of a bucket can be affected by the size and shape of the bucket, the amount of water in the bucket, the force of gravity, and the angle at which the bucket is flipped.

## 4. Why does water flow faster or slower in and out of a narrow vs. wide bucket?

The flow of water is affected by the size and shape of the bucket. In a narrow bucket, the water has less space to flow through, causing it to flow faster. In a wide bucket, the water has more space to flow through, causing it to flow slower.

## 5. How does the flow of water in and out of a bucket relate to real-life situations?

The flow of water in and out of a bucket is similar to other real-life situations, such as filling and emptying a bathtub, pouring a drink from a bottle, or draining a sink. It all involves the force of gravity and the displacement of air to create a smooth flow of water.

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