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The reading of pressure-metre attached with a closed pipe is \(3.5 \times 10^{5} \mathrm{~N} / \mathrm{m}^{2}\). On opening the valve of the pipe, the reading of the pressure-metre is reduced to \(3.0 \times 10^{5} \mathrm{~N} / \mathrm{m}^{2}\). Calculate the speed of the water flowing in the pipe

Short Answer

Expert verified
The speed of the water is 10 m/s.

Step by step solution

01

Identify Known Values

First, we identify the known values from the problem statement. The initial pressure reading is \(3.5 \times 10^{5} \mathrm{~N} / \mathrm{m}^{2}\) and the reduced pressure after opening the valve is \(3.0 \times 10^{5} \mathrm{~N} / \mathrm{m}^{2}\).
02

Apply Bernoulli's Equation

Bernoulli's equation states that the sum of pressure energy, kinetic energy, and potential energy per unit volume is constant along a streamline. In this scenario, potential energy change can be neglected. Therefore, \[ P_1 + \frac{1}{2} \rho v_1^2 = P_2 + \frac{1}{2} \rho v_2^2 \] where \( P_1 = 3.5 \times 10^5 \mathrm{~N}/\mathrm{m}^2 \), \( P_2 = 3.0 \times 10^5 \mathrm{~N}/\mathrm{m}^2 \), and the velocity change is what we are solving for (\(v\)).
03

Simplify the Equation

Since initially the velocity \(v_1\) before opening the valve is essentially zero (no flow), the equation simplifies to \[ 3.5 \times 10^5 = 3.0 \times 10^5 + \frac{1}{2} \rho v^2 \] Rearranging gives: \[ \frac{1}{2} \rho v^2 = 0.5 \times 10^5 \]
04

Substitute and Solve for Velocity

Assuming water density \( \rho \approx 1000 \text{ kg/m}^3 \), substitute in the equation \[ \frac{1}{2} \times 1000 \times v^2 = 0.5 \times 10^5 \] \[ 500v^2 = 0.5 \times 10^5 \] Divide by 500: \[ v^2 = 100 \] Taking the square root: \[ v = 10 \text{ m/s} \]
05

Conclusion

The velocity of the water in the pipe after the valve is opened is 10 m/s.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Fluid Dynamics
Fluid dynamics is the study of how liquids and gases move. It's a branch of physics that deals with understanding the flow behaviors of fluids. In fluid dynamics, there are several principles that help describe and predict how fluids will behave in different conditions. One key rule is Bernoulli’s Equation, which we used to solve the exercise. This principle tells us how pressure and velocity are related in a moving fluid.

In simple terms, when the speed of a fluid increases, its pressure decreases and vice versa. This is because energy is conserved in a closed system, meaning that if a fluid moves faster, some of the energy needed for that motion comes from its own internal pressure. Practical applications of fluid dynamics can be seen in various fields, such as engineering designs for aircrafts, water management, and even meteorology.

Engineers and scientists rely on fluid dynamics to create efficient systems for fluid transport and to better understand natural phenomena. Knowing how pressure and velocity work together helps them design things like pipes, dams, and even vehicles that move through water or air.
Pressure Differences
Pressure differences are crucial in understanding fluid flow. Pressure is the force exerted by a fluid per unit area, and differences in pressure are what make fluids move from one place to another. A practical way to think about this is imagining a balloon: when you puncture it, the air inside rushes out because the pressure inside the balloon is higher than outside.

In the original exercise, the pressure meter showed two different readings before and after opening the valve. Initially, the pressure inside the pipe was higher. Once the valve was opened, the pressure fell, indicating the water began to move. This change in pressure allowed the water to flow and demonstrated Bernoulli’s principle in action.

Pressure differences are not only important in pipes, but they also have wider implications. In meteorology, for instance, differences in atmospheric pressure drive wind patterns. In human biology, our circulatory system relies on differences in blood pressure to ensure blood flows through our veins and arteries.
Water Flow Velocity
Water flow velocity refers to how fast water is moving in a particular direction. It's an essential concept within fluid dynamics as it affects how fluids are managed in systems, like how fast water travels through a pipe leading to your faucet.

In terms of calculations, water flow velocity is typically solved using Bernoulli's Equation, especially in situations where pressure and kinetic energy changes are involved. As per the exercise, once the valve was opened, we noticed a drop in pressure as the water began moving, leading to an increase in velocity. The original exercise showed us how to calculate this velocity using known values of pressure and water density.

Understanding water flow velocity helps engineers and scientists devise systems that need to control fluid delivery and movement. It's important in designing anything from household plumbing systems to large-scale irrigation projects or hydropower plants.

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Most popular questions from this chapter

A steel cube weighs \(\mathrm{I} \mathrm{kg}\) in air and \(0.88 \mathrm{~kg}\) in water. The density of the steel is \(7.71 \times 103 \mathrm{~kg} / \mathrm{m}^{3}\) and of water is \(10^{3} \mathrm{~kg} / \mathrm{m}^{3}\). Which statements are correct? (a) The cube must be solid (b) The cube must be hollow (c) The cube consists of pure steel (d) The cube consists of impure steel

If a liquid rises to the same height in two capillaries o \(\lceil\) the same material at the same temperature (a) the weight of liquid in both capillarics must be equal (b) the radius of meniscus must be cqual (c) the capillarics must be cylindrical and vertical (d) the hydrostatic pressure at the base of capillarics must be same

A uniform plank is resting over a smooth horizontal floor and is pullcd by applying a horizontal force at its one end, Which of the following statements are not correct? (a) Stress developed in plank material is maximum at the end at which force is applied and decreases linearly to zero at the other end (b) A uniform tensile stress is developed in the plank material (c) Since, plank is pulled at one end only, therefore, plank starts to accelerate along direction of the force. Hence, no stress is developed in the plank material. (d) None of the above

A material has density \(\rho\) and bulk modulus \(k\). The increase in the density of the material when it is subjected to an external pressure \(P\) from all sides is (a) \(\frac{P}{\rho k}\) (b) \(\frac{k}{\rho P}\) (c) \(\frac{\rho P}{k}\) (d) \(\frac{\rho k}{P}\)

A liquid of density \(\rho\) flows steadily through a tube of radius \(r\) at a speed \(v\). The least power of the cnginc to maintain this rate of flow is (a) \(\frac{\pi r^{2} v}{2 \rho}\) (b) \(\frac{\pi r^{2} v^{2} \rho}{2}\) (c) \(\rho \pi r^{2} v^{3}\) (d) \(\frac{\pi r^{2} \rho}{2 v}\)

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