Bernoulli Equation - Units Question

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Homework Help Overview

The discussion revolves around the Bernoulli equation, specifically focusing on the units associated with each term when divided by density (ρ). The original poster expresses confusion regarding how the terms in the equation can be interpreted as having pressure units.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to clarify the units of the terms in the Bernoulli equation, particularly questioning the middle term's classification as having pressure units. Participants engage in correcting misunderstandings about the units of velocity.

Discussion Status

The discussion is ongoing, with some participants providing clarifications and corrections regarding the units of velocity and their implications for the Bernoulli equation. There is an acknowledgment of confusion, but no explicit consensus has been reached.

Contextual Notes

There is a mention of the original poster's misunderstanding of the units of velocity, which may have contributed to their confusion about the Bernoulli equation. Additionally, informal comments about needing coffee and sleep indicate a casual tone among participants.

JJBladester
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Homework Statement



My book says that each term in the Bernoulli equation (when divided by ρ, has pressure units). I don't see how.

Homework Equations



The Bernoulli equation for steady, incompressible flow is:

\frac{P}{\rho}+\frac{V^{2}}{2}+gz=constant

The Attempt at a Solution



Multiplying the Bernoulli equation by density (ρ), we get:

P+\rho\frac{V^{2}}{2}+\rho gz=constant

ρ = kg/m3 units

V2=m6 units

ρV2=kg*m3 units

How does the middle term in the Bernoulli equation with the units listed above count as having pressure units?

Pressure = Force/Area = Newtons/m2= \frac{\frac{kg\cdot m}{s^2}}{m^2}=\frac{kg}{m\cdot s^2}
 
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Hi JJBladester! :smile:
JJBladester said:
V2=m6 units

Nooo :redface:

V is velocity! :biggrin:

(btw, Bernouilli's equation is essentially a conservation of energy equation, which is why you get a sort-of mv2/2 term :wink:)
 
tiny-tim said:
Hi JJBladester! :smile:
Nooo :redface:

V is velocity! :biggrin:

I need more coffee. Wow, I wish I could unpost that last post.

Thanks for the reply, though. It makes a lot of sense now.
 
JJBladester said:
I need more coffee.

nooo, you need more sleep! :zzz: :wink:
 

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