Gas Pressure units:
Pressure is an
expression of force exerted on a surface per unit area. Pressure is one of
measurable properties of a gas. To drive the unit of pressure we begin with
velocity and acceleration.
Velocity is
defined as the change in distance with elapsed time; that is,
Velocity = distance moved / elapsed time
The SI unit for
velocity is m/s or cm/s.
Acceleration is
the change in velocity with time, or:
Acceleration = change in velocity /time
Force = mass X acceleration
Acceleration is
measured in m/s2 (or cm/s2). The second law of motion,
formulated by Sir Isaac Newton in the late seventeenth century, defines another
term, from which the units of pressure are derived, namely, force. According to
this law,
1N = 1kgm/s2
In this
context, the SI unit of force is the newton (N), where:
Pressure = force / area
The SI unit of
pressure is the pascal (Pa), defined as one newton per square meter:
1Pa = 1N/m2
1atmosphere = 1bar
1atmosphere=101.325kilopascal
1bar = 100000 pascal
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