What are stress and pressure? What is the unit of pressure?
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The pressure of a liquid refers to the vertical force exerted on it per unit area, commonly denoted by p. Pressure is the same concept as force; they are synonyms, and in physics it is referred to as pressure ； In hydraulics and pneumatics, it becomes pressure. The legal unit of measurement for pressure is Pa or MPa.
Physically, pressure is a force that acts perpendicularly on the surface of an object; its unit is the Newton, or N. Pressure intensity is the force applied per unit area, and it is expressed as pressure/area, with the unit being Pascal, or Pa. In engineering, pressure refers to the physical pressure intensity. There are various units for it, such as engineering units, international units, and imperial units.
In simple terms: Pressure is the force that acts vertically on the surface of an object; its unit is N (newton). Stress, in physics, refers to the pressure per unit area, and its unit is Pa (N/m2). For example, if a container filled with a certain amount of water is placed horizontally on a flat surface (as shown in the left image), and then turned upside down (as shown in the right image), the pressure and stress exerted by the water on the bottom of the container change as follows: the pressure decreases, while the stress remains unchanged. Since a sealed bucket contains a certain amount of water with no gaps inside, when the bucket is turned upside down, the height of the water column stays the same; therefore, the stress exerted by the water on the bottom of the bucket remains unchanged. When the bucket is turned upside down, it becomes wider at the top and narrower at the bottom. According to the formula F=ps (pressure = force per unit area times the area under pressure), as s decreases, the pressure exerted by the water on the bottom of the container also decreases.
The unit of pressure can also be expressed as kilogram-force, and the unit of stress can also be expressed as kilograms
The pressure of a liquid refers to the vertical force exerted on it per unit area, commonly denoted by p. Pressure is the same concept as force; they are synonyms, and in physics it is referred to as pressure ； In hydraulics and pneumatics, it becomes pressure. The legal unit of measurement for pressure is Pa or MPa. The legal unit of measurement for pressure is Pa (pascal, N/m2) or MPa (megapascal), with 1 MPa = 106 Pa
I learned in middle school physics that when the pressure remains constant, a larger area results in lower pressure, while a smaller area leads to higher pressure. So I’m a bit confused by what you’re saying; could you please explain?
In engineering, what is referred to as pressure is the effect of pressure; therefore, pressure in engineering is equivalent to stress in physics