Pressure in fluids

Annotations:

• Thrust A force acting on a surface is called thrust. Measured in dynes in CGS system and newtons in SI system.
• Pressure The force acting normally on unit surface area is called pressure.

1. Thrust A forever acting normally on a surface is called thrust. Measured in dynes in CGS system and newtons in SI system.
2. Pressure The force acting normally on a surface area is called pressure.
   1. Pressure = Thrust upon Area
   2. Pressure is a scalar quantity.
   3. Unit of pressure When a force of 1N acts normally on an area of 1 sq.m , then the pressure acting on that surface is called 1 pascal.
3. Fluids Any substance which has no fixed shape and can follow is called fluids
   1. The momentum imparted per second by the molecules to a given surface gives rise to average force acting on the surface. This average force acting per unit area gives rise to fluid pressure
4. Factors on which the pressure at a point in fluid depends.
   1. Pressure in fluids is directly proportional to its height (or depth)
   2. Pressure in a fluid is directly proportional to its density
   3. Pressure in a fluid is directly proportional to the acceleration due to gravity.
   4. Pressure in a fluid is independent if the area of cross section.
5. Laws of fluid pressure
   1. Pressure at a point inside the liquid increases with the depth from the free surface of the liquid.
   2. Pressure at a point inside the liquid at a given depth increases with the increase in the density of the liquid.
   3. Pressure is same in all directions, about a given point within the liquid
   4. Pressure is same at all points in horizontal plane at a given depth in a stationary liquid
   5. A liquid seeks its own level
6. The force exerted by the air on a unit surface area is called atmospheric pressure.
   1. Measured using barometer
      1. Fortin's Barometer
      2. Mercury Barometer
      3. Aneroid Barometer