Calculating force and area using the pressure equation

The pressure equation can be rearranged to calculate either force or area, if enough values are known.

pressure~(Pa) = \frac{force~normal~to~a~surface~(N)}{area~of~that~surface~(m^2)}

Example

A pressure of 280 Pa acts at 90° to an area of 0.04 m2. What force is exerted at 90° to the area?

First rearrange the equation to find force normal to surface area:

force normal to a surface area = pressure × area of that surface

Next substitute the values into the equation:

force = 280 × 0.04

force = 11.2 N

Question

A fluid exerts a pressure of 150 kPa at right angles to a wall of area of 180 m2. Calculate the force on the wall.

First convert 150 kPa to Pa:

150 × 1,000 = 150,000

Next substitute the values into the equation:

force normal to a surface area = pressure × area of that surface

force = 150,000 × 180

force = 27,000,000 N