Air Pressure and Net Force on a Door in a Tornado

In summary, the problem asks to calculate the net force exerted on a door by a sudden 15 percent decrease in normal atmospheric pressure caused by a tornado. The formula used is P=F/A, where P represents pressure, F is force, and A is area. After some calculations, the answer was found to be 15,083,250 Pa, which was later corrected to be in force units instead of pressure units. The problem also reminds to consider the presence of a full atmosphere of pressure pushing on the other side of the door.
  • #1
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Homework Statement


In a tornado, the pressure can be 15 percent below normal atmospheric pressure. Suppose that a tornado occurred outside a door that is 195 cm high and 91 cm wide. What net force would be exerted on the door by a sudden 15 percent drop in normal atmospheric pressure? In what direction would the force be exerted?


Homework Equations


Here lies the problem.
I do no know which formula I should be using.
I know that atmospheric pressure is about 1.0 x 10^5 N/m squared at sea level.
Which I'm inferring is what I would use for the problem.
Could someone post a formula or something?
I think that's all I would need.
 
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  • #2
Never mind.
I just realized that P=F/A would work.
Whoops xP
 
  • #3
So I tried doing the problem:
P=F/A
Regular pressure = 1.0 x 10^5
15% decrease = 8.5 x 10^3
85000 = F/(195 x 91)
= F/177.45<--- Converted to meters
So I multiplied by the area:
85000 x 177.45=15,083,250 Pa
And that, to me, seems like a completely ridiculous answer.
Would someone care to correct or at least help me?
 
  • #4
A couple of comments:

1. Remember there is a net force, due 1 full atmosphere of pressure, pushing on the other side of the door.

2. Be careful with the units. It asks for a force, you're answer was in Pa units. Do you see the problem there?
 

1. What is air pressure?

Air pressure is the force exerted by the weight of air on a surface. It is the result of the constant movement of air molecules and is measured in units called atmospheres (atm) or pascals (Pa).

2. How does air pressure affect weather?

Air pressure plays a crucial role in determining weather patterns. Low air pressure typically brings cloudy and stormy weather, while high air pressure is associated with clear and sunny skies.

3. How is air pressure measured?

Air pressure is measured using an instrument called a barometer. There are two main types of barometers: mercury barometers, which use the height of a column of mercury to measure pressure, and aneroid barometers, which use a sealed, flexible container to measure pressure changes.

4. Can air pressure be changed?

Yes, air pressure can be changed. It is affected by factors such as temperature, humidity, and altitude. For example, as temperature increases, air molecules become more active and spread out, resulting in lower air pressure.

5. How does air pressure affect the human body?

Air pressure changes can affect the human body, particularly at high altitudes. As air pressure decreases with altitude, the amount of oxygen in the air also decreases. This can lead to altitude sickness, which can cause symptoms such as headache, dizziness, and shortness of breath.

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