Pressure, Torricelli's principle and Pascal's principle

Fundamental concepts in physics and engineering related to pressure.
Pressure
Pressure is the force per unit area exerted on a surface.
Types of Pressure
1. *Absolute Pressure*: Pressure measured with respect to vacuum.
2. *Relative Pressure*: Pressure measured with respect to atmospheric pressure.
3. *Hydrostatic Pressure*: Pressure exerted by a fluid in equilibrium.
4. *Atmospheric Pressure*: Pressure exerted by the Earth's atmosphere.
Torricelli experiment
He demonstrated the existence of atmospheric pressure using a mercury tube.
Pascal's Principle
It states that the pressure applied to a fluid at one point is transmitted equally in all directions.
Applications
1. *Hydraulic Engineering*: Design of irrigation and sewage systems.
2. *Mechanical Engineering*: Design of machines and fluid systems.
3. *Medicine*: Study of blood and respiratory pressure.
4. *Aviation*: Study of atmospheric pressure and altitude.
Formulas
1. *Absolute Pressure*: Pabs = Patm + Pref
2. *Relative Pressure*: Pref = Pabs - Patm
3. *Hydrostatic Pressure*: Phidro = ρ × g × h
4. *Pascal's Principle*: P1 / A1 = P2 / A2
Units
1. *Pascal (Pa)*: SI unit of pressure.
2. *Atmospheres (atm)*: Unit of atmospheric pressure.
3. *Bar*: Pressure unit used in meteorology.
Importance
1. *Understanding pressure*: Fundamental to designing systems and machines.
2. *Safety*: Know the pressure to avoid accidents.
3. *Innovation*: Applications in technology and science.