Can someone give me a pitot tube question

[PreMade]

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Seriously, I can't figure out how this works.

I watched khan's video but they did a terrible job explaining it.

I try to look up some questions I can work through but can't find any.

Does anybody have a good question that might be presented on the mcat that can help me conceptually?

 

[basophilic]

I thought KA did a good job with it; try wikipedia
The whole point of it is to detect a pressure difference between the two chambers of the tube to determine the speed of the surrounding air (and if you're aware of the speed of the surrounding air/water, then you can use it to predict speed that an airplane or ship or submarine are traveling at)
So you could be given a pressure difference and the density of the fluid and asked to figure out velocity; or you could be given velocity of a ship/submarine/airplane and the depth at which they're at and asked to calculate stagnation pressure - for this you'd determine gauge pressure and then solve for stagnation pressure; would a denser liquid (sea vs. fresh water) allow a submarine to travel faster or slower, assuming a constant stagnation pressure; etc.

 

[PreMade]

Thanks for the explanation, it makes better sense now.

Can you tell me if I have this right?

Total pressure = atm pressure + gauge pressure (gauge pressure = pressure underwater = density*gravity*height)

Stagnation pressure = pressure at a specific point (the pressure on the hole opening to the tube or wall at the end of tube?)

Density is the density of the fluid

So, if the density of the fluid increase that make the velocity slower?

 

[basophilic]

Thanks for the explanation, it makes better sense now.

Can you tell me if I have this right?

Total pressure = atm pressure + gauge pressure (gauge pressure = pressure underwater = density*gravity*height)

Stagnation pressure = pressure at a specific point (the pressure on the hole opening to the tube or wall at the end of tube?)

Density is the density of the fluid

So, if the density of the fluid increase that make the velocity slower?

Your definition of stagnation pressure is correct; the total pressure one is correct if you mean this pressure to denote the static pressure in the bottomright chamber of the tube.
Here's a simple application scenario for an underwater system:
If you're underwater, then the static pressure (pressure in the right chamber; P1 in above diagram) will consist of the gauge and atmospheric pressure since that's the static equilibrium condition, and we'll be using that as a reference point. When the pitot tube is moving, water rushes in head-on into the bottom chamber and creates the stagnation pressure in the left chamber; this stagnation pressure (Ps in the above image) pushes onto the flexible membrane between the two compartments (you'll have a flexible membrane in the bottom region of the tube separating the two chambers). Sensors will sense the pressure differential and send it to the ship/submarine's computing system. This system will use the equation in the above diagram to calculate the ship's speed and let the captain know.