Conceptual question: Atmospheric pressure

In summary, the conversation discusses the flow of water from a faucet to a sink and the application of Bernoulli's equation to determine the velocity at the bottom of the sink. The solution is v = 2.81 m/s. The question is raised about the role of atmospheric pressure on both the top and bottom of the stream, and a request for clarification is made. A follow-up "bump" is also mentioned.
  • #1
johnj7
27
0

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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  • #2
sorry but can anyone answer / help me out?


bump (is this allowed?)
 
  • #3
Shouldn't there be a kinetic energy term on the left-hand side of the equation?
 

Related to Conceptual question: Atmospheric pressure

1. What is atmospheric pressure?

Atmospheric pressure is the force per unit area exerted by the weight of the Earth's atmosphere. It is commonly measured in units of pressure called atmospheres (atm) or in millimeters of mercury (mmHg).

2. How is atmospheric pressure measured?

Atmospheric pressure is measured using a device called a barometer. The most common type is a mercury barometer, which measures the height of a column of mercury in a glass tube. Other types include aneroid barometers and electronic barometers.

3. What causes changes in atmospheric pressure?

The main cause of changes in atmospheric pressure is the movement and distribution of air in the atmosphere. Factors such as temperature, humidity, and wind can also affect atmospheric pressure.

4. What are the effects of high and low atmospheric pressure?

High atmospheric pressure is associated with clear, dry weather while low atmospheric pressure is associated with cloudy, wet weather. Extreme changes in atmospheric pressure can also have effects on human health, particularly for those with respiratory conditions.

5. How does altitude affect atmospheric pressure?

As altitude increases, atmospheric pressure decreases. This is because there is less air above you to exert pressure. For every 1000 meters increase in altitude, atmospheric pressure decreases by about 10%. This can have effects on human health and activities, such as breathing and boiling points of liquids.

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