the definition of pressure says that this magnitude is given for the reason of a strength applied perpendicularly over a surface and the surface area. Mathematically, we have:
notice that pressure and area they are inversely proportional quantities.
Some examples from everyday situations can help in understanding the concept of pressure. For starters, we can mention the act of sharpening knives. The purpose of sharpening a knife is to make the contact area of the blade with the object to be cut is as small as possible. Therefore, it will not be necessary to apply a very large force to the knife handle.
For walk in snow without sinking or to avoid breaking ice sheets on which you walk, you can use snow shoes like the ones in the image below. Thus, the weight of those who walk will be distributed over an area greater than the area of the feet, reducing the pressure exerted on the ground.
O sphygmomanometer (equipment that measures the blood pressure) should be used at a height close to the heart, as this ensures that the pressure measured by the equipment corresponds to the blood pressure.
Is pressure a vector or scalar quantity?
The pressure is considered a scalar greatness. Operations involving pressure are always algebraic, never vector (click on here to know the operations of the vector type). Another reason that pressure is understood as a scalar quantity is that the pressure exerted by a fluid on a body acts in all directions, so it makes more sense to understand this magnitude as scaling rather than as vector.
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Pressure exerted by a fluid
The call Steve's Law defines that the pressure exerted by a fluid depends on the density of the fluid (ρ), of the gravitational attraction location (g) and the height of the column of liquid (h). Without considering atmospheric pressure, we have:
When the fluid in question is water, Stevin's Law shows us that the pressure exerted by a column of water 10 m high corresponds approximately to normal atmospheric pressure (1 atm).
Atmospheric pressure
THE atmospheric pressure it is the pressure that the air layer makes on the earth's surface. Atmospheric pressure is considered normal for points at sea level. For higher and higher points, the amount of air decreases and the atmospheric pressure decreases.
THE atmospheric pressure measurement was made in the 17th century by the Italian physicist Evangelist Torricelli. He found that the pressure exerted by the atmosphere corresponded to the pressure of a column of mercury (Hg) 76 cm high. Therefore, normal atmospheric pressure is 76 cmHg or 760 mmHg.
1 atm = 1 x 105 Pa (N/m2) = 76 cmHg = 760 mmHg
By Joab Silas
Graduated in Physics
Would you like to reference this text in a school or academic work? Look:
JUNIOR, Joab Silas da Silva. "What is pressure?"; Brazil School. Available in: https://brasilescola.uol.com.br/o-que-e/fisica/o-que-e-pressao.htm. Accessed on June 28, 2021.
