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Pressure - OCR GatewayThe pressure equation

Every living thing on Earth is in balance with the pressure of the air or water around it. Pressure helps blood to move around the body and allows organisms to breathe.

Part of Physics (Single Science)Forces

The pressure equation

The 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掳 to an area of 0.04 m2. What force is exerted at 90掳 to the area?

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

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

Next substitute the values into the equation:

force = 280 脳 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.