Final answer:
Pressure is calculated as force per unit area and expressed in pascals. For atmospheric pressure and other scenarios, the weight acting over an area is divided by that area to find the pressure exerted.
Step-by-step explanation:
Pressure is defined as the force exerted per unit area. According to the formula p = f/a, where p is pressure, f is force, and a is area, we can calculate the pressure exerted on an area in terms of mass (m), acceleration due to gravity (g), known atmospheric pressure (pa), and the area of the top of each layer (a).
The SI unit for pressure is the pascal (Pa), which is equivalent to one newton per square meter (1 N/m²). Atmospheric pressure at sea level averages around 101 kPa or 1 atmosphere (atm), which is the same as 760 mmHg or the pressure required to support a column of mercury 760 mm tall.
To calculate the pressure at any given point, one would need to know the force applied and the area over which it is applied. This could include the weight of the atmosphere above that point (m·g) or the weight of any object pressing down on a surface.
By dividing this force by the area a on which the force is exerted, we determine the pressure at that location. In the case of atmospheric pressure, this would involve calculating the weight of the air above the area a and dividing by the same area.