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## Main Question or Discussion Point

Please tell me if I am understanding this correctly, or please point out where im going wrong....

imagine you have an open ended u-shaped tube filled with water. The pressure on left side of the U is the same as pressure at right side, because they are both open to atmospheric pressure pushing down on the water surface, right?

OK, so then you put a rubber stopped on the right side (the bottem of the stopped is in contact with water, so theres no "air pocket)

Am I correct in saying that the pressure on the left is greater than the pressure on the right, because the left has atm pressure pushing on surface, yet the right side is not open to atm, so it doensnt have atm pressure?

so pressure on left (zero depth) is 101325Pa, and pressure on right (zero depth) is approx zero. --a vacuum. Is that correct?

if that is correct then (here is what confuse me..):

... is there a force that pushes up against the stopper? If so, then there must be force from the stopper onto the water surface (3rd law force pair), and if that is true then there actually IS pressure on the stoppered end, exactly equal (because the U-shaped tube isnt accelerating obviously) to the atm pressure that pushes down on the left side (the open ended side).

Please help clarify and thanks alot for any help

imagine you have an open ended u-shaped tube filled with water. The pressure on left side of the U is the same as pressure at right side, because they are both open to atmospheric pressure pushing down on the water surface, right?

OK, so then you put a rubber stopped on the right side (the bottem of the stopped is in contact with water, so theres no "air pocket)

Am I correct in saying that the pressure on the left is greater than the pressure on the right, because the left has atm pressure pushing on surface, yet the right side is not open to atm, so it doensnt have atm pressure?

so pressure on left (zero depth) is 101325Pa, and pressure on right (zero depth) is approx zero. --a vacuum. Is that correct?

if that is correct then (here is what confuse me..):

... is there a force that pushes up against the stopper? If so, then there must be force from the stopper onto the water surface (3rd law force pair), and if that is true then there actually IS pressure on the stoppered end, exactly equal (because the U-shaped tube isnt accelerating obviously) to the atm pressure that pushes down on the left side (the open ended side).

Please help clarify and thanks alot for any help