Understanding Fluid Pressure: Get Help Here!

In summary, the conversation discusses the concept of fluid pressure at different points in a fluid at rest. It is mentioned that at the same depth, the pressure at any two points is equal, but because one end is open, the pressure at point C is less than B and equal to A. The pressure at point A and D is due to atmospheric pressure, while the weight of water molecules above point B causes it to experience more pressure. The reason for the lower pressure at point C compared to B is because the fluid at point C has to be accelerated towards the outlet pipe, creating a pressure variation from higher to lower pressure.
  • #1
blahraptors
2
0

Homework Statement


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Homework Equations


fluid pressure = fluid density * depth * g

The Attempt at a Solution


My understanding is that fluid pressure at any two points at the same depth is equal, for a fluid at rest. But because one end is open, the pressure at point C is less than B and equal to A? I don't understand intuitively how this works.

Any help would be appreciated - thanks!
 
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  • #2
Well at point A - what is exerting the pressure?
What about at point D?

Would this be a high or a low pressure compared with the rest?

Remains to consider B and C ... what is exerting the pressure in each case?
Is there anything else that would contribute to the pressure?
 
  • #3
At point A, we have atmospheric pressure, as does point D, so they are equal I think. B has the weight of the water molecules above it, so it experiences more pressure than A and D. I'm just not sure why C is < B when they are at the same depth. Is it because molecules at C are moving but not at B?
 
  • #4
I'm just not sure why C is < B when they are at the same depth. Is it because molecules at C are moving but not at B?
That's the one - notice that B is placed conspicuously far away from the entrance to the pipe that C is in.

You could also look at it like this: The pressure has to drop as you approach D or A.
C is closer to the low pressure region than B is.
 
  • #5
What's happening is that the fluid that is approaching the outlet pipe has to get accelerated from the very low velocity away from the pipe (e.g., at point B ) to the higher velocity at point C. To accelerate it, you need an imbalance of force. This is supplied by a pressure variation, from higher pressure away from the pipe entrance to lower pressure within the pipe.
 

FAQ: Understanding Fluid Pressure: Get Help Here!

What is fluid pressure?

Fluid pressure is the force per unit area exerted by a fluid, such as a gas or liquid, on an object. It is determined by the density of the fluid, the depth or height of the fluid, and the acceleration due to gravity.

How is fluid pressure measured?

Fluid pressure is typically measured using a manometer, which is a device that measures the difference in fluid levels between two points. In some cases, pressure gauges may also be used to measure fluid pressure.

What factors affect fluid pressure?

The three main factors that affect fluid pressure are the density of the fluid, the depth or height of the fluid, and the acceleration due to gravity. Other factors that may also affect fluid pressure include temperature and the shape of the container holding the fluid.

How does fluid pressure relate to buoyancy?

Fluid pressure plays a key role in the concept of buoyancy, which is the upward force exerted by a fluid on an object immersed in it. This force is equal to the weight of the fluid displaced by the object and is determined by the fluid's density and the depth of the object.

What are some real-world applications of understanding fluid pressure?

Understanding fluid pressure is important in many fields, including engineering, physics, and meteorology. It is used in designing and constructing structures, such as dams and bridges, and in predicting weather patterns. It is also essential in the functioning of hydraulic systems, such as brakes and lifts.

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