Piston cylinders are a common component for many mechanical systems. Cylinders are also an excellent case study for the concept of [[Pressure|pressure]].
![[Piston_Cylinder_2.png|500]]
The piston can move up and down the cylinder. The surface pressure of the [[Fluid|fluid(s)]] in contact with the cylinder will determine whether or not it will move. The only other [[Force|force]] acting upon the piston is its [[Mass|mass]], wall [[Friction|friction]] is neglected.
![[Piston_2.png|center|300]]
The resulting force balance will be:
$P_fA = P_0A + mg$
Where:
- $P_f$ is the pressure of the fluid
- $P_0$ is atmospheric pressure
- $A$ is the piston cross-sectional area
- $m$ is the piston mass
- $g$ is gravitational acceleration