FISICA Teoria #17 - FLUIDI, PRESSIONE, PRINCIPIO di PASCAL, LEGGE di STEVINO

Recent questions

• What is the definition of pressure?

  Pressure is defined as the ratio of the perpendicular force acting on a surface to the area of that surface. It is calculated using the formula Pressure (P) = Force (F) / Area (A). For accurate pressure measurement, the force must be the component that is perpendicular to the surface in question. This definition highlights the fundamental relationship between force and area, emphasizing how pressure is a measure of how concentrated that force is over a given area.

• How is pressure measured in different units?

  Pressure is primarily measured in Pascals (Pa), where 1 Pascal is equivalent to 1 Newton per square meter (N/m²). Other common units of pressure include Atmospheres (atm), where 1 atm is approximately 101,325 Pa, and Bars, where 1 Bar equals 100,000 Pa. Additionally, pressure can be expressed in Millimeters of Mercury (mmHg), with 760 mmHg equating to 1 atm. Understanding these units is crucial for interpreting pressure measurements in various scientific and engineering contexts, as different fields may prefer specific units based on convention or application.

• How does weight affect pressure on surfaces?

  The weight of an object significantly influences the pressure it exerts on a surface, which is determined by the formula Pressure (P) = Force (F) / Area (A). For instance, Rocco, who weighs 120 kg, exerts a pressure of 235,440 Pa on a surface area of 50 cm². In contrast, Aunt Maria, weighing 60 kg and standing on a stiletto heel with a much smaller surface area of 0.5 cm², exerts a pressure of approximately 11,000,000 Pa. This example illustrates that even a lighter person can exert much higher pressure if they have a smaller contact area, demonstrating the critical role of surface area in pressure calculations.

• What is Pascal's principle in fluids?

  Pascal's principle states that when pressure in a fluid increases, this change is transmitted uniformly throughout the fluid and to all surfaces it contacts. This principle is particularly important in hydraulic systems, where a small force applied to a small area can lift a larger weight over a larger area. The uniform transmission of pressure allows for the efficient transfer of force, making hydraulic systems effective for various applications, such as in machinery and automotive brakes, where they amplify force to perform work.

• How does depth affect pressure in fluids?

  The pressure at a certain depth in a fluid increases due to the weight of the fluid above it. This relationship is quantified using the formula Pressure (P) = Density (ρ) × Gravity (g) × Depth (h) + P₀, where P₀ is the atmospheric pressure at the surface. For example, at the Mariana Trench, which is approximately 11,000 meters deep, the pressure reaches about 110 million Pa, factoring in the density of seawater and gravitational acceleration. As one descends underwater, the increasing pressure can cause objects not designed for such conditions to crumple, highlighting the significant impact of fluid pressure in various environments.