Which of the following are not units of pressure?
Pressure is a fundamental physical quantity that measures the force exerted per unit area. It is an essential concept in various scientific and engineering fields, such as fluid mechanics, thermodynamics, and materials science. However, not all units used to express pressure are recognized as standard units. In this article, we will explore some units that are not considered valid units of pressure.
Firstly, let’s consider the unit “pound per square inch” (psi). While psi is commonly used in the United States to measure pressure, it is not an internationally recognized unit of pressure. The International System of Units (SI) defines the Pascal (Pa) as the standard unit of pressure, which is equivalent to one Newton per square meter (N/m²). Therefore, psi is not a unit of pressure in the SI system.
Another example is the “bar,” which is often used in Europe. Although the bar is not an SI unit, it is still widely recognized and used in various applications. However, the bar is not considered a standard unit of pressure in the SI system. The SI unit for pressure is the Pascal, and the bar is only used as a supplementary unit.
The unit “torr” is another example of a non-standard unit of pressure. Torr is commonly used in the field of vacuum technology and is defined as 1/760 of an atmosphere. While torr is a recognized unit, it is not part of the SI system. The SI unit for pressure is the Pascal, and torr is only used as a supplementary unit.
In addition to these, there are several other units that are not considered standard units of pressure. For instance, “pound-force per square foot” (psf) is used in some engineering applications, but it is not an SI unit. Similarly, “poundal per square foot” (pd/ft²) is another unit that is not part of the SI system.
In conclusion, while there are various units used to express pressure, not all of them are recognized as standard units. The International System of Units (SI) defines the Pascal (Pa) as the standard unit of pressure, and other units such as psi, bar, torr, psf, and pd/ft² are considered supplementary units or non-standard units. It is important to use the correct units when dealing with pressure in scientific and engineering contexts to ensure consistency and accuracy in calculations and measurements.
