Calculating the air pressure exerted on the body

In summary, to calculate the air pressure exerted on an average human of 1.9m2, you need to find the volume of the body, the density of air, and multiply them by the acceleration of gravity. This will give you the net upward force in Newtons, which is not properly expressed in units of pressure. Archimedes' principle states that the net force is equal to the weight density of the fluid multiplied by the volume of the fluid displaced by the body.
  • #1
mateusz24052
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Good morning all,

How do you calculate the air pressure exerted on an average human of 1.9m2

I know the air pressure is 1.01kPa.

Do I do, F = PA? 1.01kPa x 1.9?

What are the calculations step by step? and what is it in bars?

Does that mean it is 1.919 bar?

Thank you,
 
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  • #2
mateusz24052 said:
What are the calculations step by step? and what is it in bars?
Archimedes worked it out a long time ago.

Force is a vector quantity. If you add up the force from pressure on all parts of your body, most of it will cancel out. The force on your front side will cancel the force on your back. The force on your left side will cancel out the force on your front. The force on your bottom side will almost cancel the force on your top side.

The reason that the vertical force from pressure does not exactly cancel is that air pressure is just a bit higher at your feet than at your head.

What Archimedes worked out is that the net force is given by the [weight] density of a fluid multiplied by the volume of that fluid which is displaced by a body.

So find the volume of your body. Your mass in kilograms will be pretty close to your volume in liters.

Find the density of air in kilograms per liter. (Google says 0.129 grams per liter. So 0.000129 kg/l)

Multiply the two and multiply by the acceleration of gravity. (9.8 meters/sec2)

The result will be the net upward force in Newtons.

Note that the 1.9 m2 surface area does not enter into this calculation. Nor is the result properly expressed in units of pressure. If you sum a pressure over a surface you get a force.
 
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What is air pressure?

Air pressure is the force exerted by the weight of air molecules in the atmosphere. It is measured in units of pressure such as pounds per square inch (psi) or pascals (Pa).

How is air pressure calculated?

Air pressure is calculated by dividing the force of the weight of air by the surface area it is exerted on. This can be done using the formula P = F/A, where P is pressure, F is force, and A is surface area.

What factors affect air pressure?

The main factors that affect air pressure include altitude, temperature, and humidity. As altitude increases, air pressure decreases. As temperature increases, air pressure decreases. And as humidity increases, air pressure increases.

Why is it important to calculate air pressure on the body?

Calculating air pressure on the body is important because it can help determine the amount of force that is being exerted on the body by the surrounding air. This is particularly important for activities such as scuba diving or high-altitude mountaineering, where changes in air pressure can have significant effects on the body.

How can air pressure on the body be measured?

Air pressure on the body can be measured using a device called a barometer. This instrument measures the atmospheric pressure and can be calibrated to measure the pressure on the body as well. Other methods include using specialized sensors or calculating pressure changes based on altitude and other factors.

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