Conceptual question: Atmospheric pressure

AI Thread Summary
Atmospheric pressure affects both the top and bottom of the water stream due to the principle that pressure acts uniformly in all directions. At the top, atmospheric pressure contributes to the overall pressure exerted on the water, while at the bottom, it balances the pressure from the water column. The Bernoulli equation accounts for energy conservation, where kinetic energy is represented by the velocity term. The inquiry about the kinetic energy term reflects a common confusion regarding the application of Bernoulli's principle. Understanding these concepts clarifies the role of atmospheric pressure in fluid dynamics.
johnj7
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Homework Statement


A stream of water flows vertically downward at a speed of v1 = 2.0 m/s from a faucet of cross sectional area A = 0.5 cm^2 to the bottom of a sink a distance h = 20 cm below.

Homework Equations


Bernoulli's
P(atm) + (rho)gh = P(atm) + 0.5(rho)v^2


The Attempt at a Solution


solution v = 2.81 m/s

I understand how to get the velocity at the bottom, but I was just wondering why atmospheric pressure acts on both the top and the bottom. I can grasp how atmospheric pressure acts on the bottom of the stream, but how does it act on the top of the stream?
 
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sorry but can anyone answer / help me out?


bump (is this allowed?)
 
Shouldn't there be a kinetic energy term on the left-hand side of the equation?
 

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