Why Would the Pressure at Points 1 and 2 be the Same?

In summary, according to Pascal's law, the pressure at points 1 and 2 should be the same due to their equal elevation. However, even though water is denser than air and exerts more pressure, the height of the air column pushing down on the water surface in the tank balances out the pressure. This allows for equal pressure at both points, maintaining static equilibrium in the system.
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colcol500
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Why would the pressure at points 1 and 2 be the same? I understand they are at the same elevation and due to Pascal's law should have the same pressure, but isn't water denser than air? So in turn, wouldn't it exert more pressure than air? So then how come despite all the water pushing down on point 2, it is still the same pressure as point 1, which only has air pushing down on it?

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It might help you to think about the height of the column of air pushing down on the surface of the water in the tank. Also, think about what would happen if the pressures were not equal.
 
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The system is supposed to be in static equilibrium. So, if you go downward beneath point 1 until you are lower than the tube, the pressure increases. Then if you go horizontally across under the edge of the tube, the pressure doesn't change. The, if you go back up within the tube to the same elevation as point 1, the pressure decreases again until you reach point 2. The net effect of this excursion is no change in pressure between points 1 and 2.
 

1. Why would the pressure at points 1 and 2 be the same?

The pressure at points 1 and 2 would be the same because they are at the same height and therefore experience the same gravitational force from the Earth. This means that the weight of the fluid above points 1 and 2 are equal, resulting in the same pressure.

2. Does the type of fluid affect the equal pressure at points 1 and 2?

No, the type of fluid does not affect the equal pressure at points 1 and 2. As long as the fluid is incompressible, the pressure at points 1 and 2 will be the same regardless of the type of fluid.

3. How does the shape of the container affect the pressure at points 1 and 2?

The shape of the container does not affect the pressure at points 1 and 2 as long as the height of the fluid at both points is the same. The pressure at a point only depends on the height of the fluid above it, not the shape of the container.

4. Can the pressure at points 1 and 2 be different if the fluid is moving?

Yes, the pressure at points 1 and 2 can be different if the fluid is moving. This is because the pressure at a point also depends on the velocity of the fluid at that point. If the fluid is moving faster at one point, the pressure at that point will be lower compared to a point with slower moving fluid.

5. What happens to the pressure at points 1 and 2 if the height of the fluid changes?

The pressure at points 1 and 2 will change if the height of the fluid changes. This is because the pressure at a point is directly proportional to the height of the fluid above it. As the height increases, the pressure also increases and vice versa.

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