1. Pressure

2. P = F/A How you apply a force can make a big difference
Pressure like torque is a way of measuring how a force is applied
Pressure (P) measures the concentration of force (F) on a surface of area (A)
P = F/A
Enough pressure can make a surface fail…
That’s how a knife cuts!
The MKS unit for Pressure is the Pascal (Pa)
1 Pa = 1 N/m²

3. Pressure Measures FPS pressure measures include: inches of Hg or water
More commonly Lb/sq.in. or PSI
MKS pressure measures include:
mm or cm of Hg/water
An “Atmosphere” (atm) is a measure based on the pressure of the air at sea level (Standard Pressure)
1 Atm = 1.01 x 105Pa or
1Atm = 14.7 PSi

4. Pascal’s Principle
Pressure applied to fluid in a closed container creates an equal amount of pressure on all walls of the container F1 F2 P = = A1 A2 This can be used as a machine… Hydraulics: Lifts, Brakes & Steering etc.

5. Gauge Pressure
Most practical pressure gauges give the difference between the pressure inside and that of the air. This is Gauge pressure