Easy Physics Concept but I cannot understand

[jmk193]

Homework Statement

Fluid is flowing from left to right through a pipe (see the drawing). Points A and B are at the same elevation, but the cross-sectional areas of the pipe are different. Points B and C are at different elevations, but the cross-sectional areas are the same. Rank the pressures at the three points, highest to lowest.


I could not attach the image but it looks like this: [ A ]---B--- , where A is thicker than B, and C is way above these two. The answer is A,B,C.

Homework Equations

P = F/A
Bernoulli's Equation maybe?

The Attempt at a Solution

I understand that Point C has the lowest pressure because it is elevated. To decipher between A and B, I am using the equation P = F/A. However, this tells me that pressure and area are inversely proportional which would suggest that Point A has a lower pressure than Point B. Where is my logic wrong?

 

[LawrenceC]

When you say A is thicker, what do you mean? Larger in internal diameter?

 

[jmk193]

yes A is larger in diameter than B.

 

[LawrenceC]

So what can you say about the velocities at A and B?

 

[jmk193]

The velocity at Point B will be greater than the velocity at Point A because area and velocity are inversely proportional according to A1v1 = A2v2.

 

[LawrenceC]

Now looking at Bernoulli's equation, what does that tell you about pressures at A and B?

 

[jmk193]

I see it now! Thank you so much!