why sir exerts pressure
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Answer:
Air not only has mass, but exerts pressure as well. The particles of air push in all directions and the force that is exerted is called air pressure.
While air pressure can refer to the pressure of air within a confined area (car tire or football), atmospheric pressure specifically refers to the air pressure exerted by the air molecules above a given point in the Earth’s atmosphere. The closer we get to the Earth, the higher the atmospheric pressure due to the weight of air particles above. This is why there is less air pressure at the top of a mountain than at sea level. The weight of air above compresses the air particles near the surface of the Earth, creating a higher density of particles. The tool used to measure atmospheric pressure is called a barometer. You cannot use a barometer to measure the air pressure inside a tire, a football, or an air mattress.
When we jump into a pool, we feel the weight of the water pressing down on us from all directions. This force is known as water pressure. The deeper you sink, the more pressure you will feel. This is because you have the weight of the water on top of you trying to compress you.
To help us visualize air pressure, imagine that we’re living at the bottom of an ocean of air. At sea level, the air pressure is greater than on the top of a mountain since you have the weight of more air pushing down on you.
How heavy is that air?
A cube of air 1 metre per side has a mass of 1 kilogram. The Earth’s atmosphere is about 480 kilometres thick. This means that on the surface of the Earth, we have 480 kilometres of air pushing down on us. That’s 1,700 kilograms on each of our heads (which is roughly the equivalent of the weight of a male hippopotamus!).
So why don’t we get flattened by all that air pressure?
We have air and fluids inside your body that exert a pressure outward, cancelling out the atmospheric pressure around us. This ensures that our bodies do not collapse under the weight of the air around us.