Terms

info

• Liquid
  • pressure of liquid is always equal, indifferent of surface area, if depth is the same

units

Equations

$$\begin{array}{c} \begin{aligned} P &= \frac{F}{A} \end{aligned} \\ \hspace{-9em}\textbf{where} \\ \begin{array}{rl} P & \text{pressure in $Pa$} \\ F & \text{force in $N$ (newtons)} \\ A & \text{area in $m^2$} \\ \end{array} \end{array}$$

In hydraulic systems,

$$\begin{array}{c} \begin{aligned} V &= A \times d \end{aligned} \\ \hspace{-9em}\textbf{where} \\ \begin{array}{rl} V & \text{volume in $m^3$} \\ A & \text{area of liquid pushed in $m^2$} \\ d & \text{distance piston is pushed in $m$} \end{array} \end{array}$$

in liquids,

$$\begin{array}{c} \begin{aligned} P &= h\rho g \end{aligned} \\ \hspace{-9em}\textbf{where} \\ \begin{array}{rl} P & \text{pressure of liquid at depth h in $Pa$} \\ h & \text{depth of liquid in $m$} \\ \rho & \text{density of liquid in $kg/m^3$} \\ g & \text{gravitational field strength in $N/kg$} \end{array} \end{array}$$

in a Mercury Barometer,

$$\begin{array}{c} \begin{aligned} 1.01 \times 10^5 Pa &= 760 mm\ Hg \end{aligned}\end{array}$$

In a Manometer, pressure at the same height in both columns are equal