ABSTRACT
The pressure acting on a surface is defined as the perpendicular force per unit area of surface. The unit of pressure is the pascal*, Pa, where 1 pascal is equal to 1 newton per square metre. Thus pressure,
p = FA pascals
At the end of this chapter you should be able to:
• define pressure and state its unit • understand pressure in fluids • distinguish between atmospheric, absolute and gauge pressures • state and apply Archimedes’ principle • describe the construction and principle of operation of different types of barometer • describe the construction and principle of operation of different types of manometer • describe the construction and principle of operation of the Bourdon pressure gauge • describe the construction and principle of operation of different types of vacuum gauge • calculate hydrostatic pressure on submerged surfaces • understand hydrostatic thrust on curved surfaces • define buoyancy • appreciate and perform calculations on the stability of floating bodies
where F is the force in newtons acting at right angles to a surface of area A square metres.
