Thrust The force applied on a surface in a direction perpendicular to the surface Unit = Newton (N)
Pressure The effect of thrust per unit area is called pressure. Pressure =thrust/area Unit – Pascal (Pa) 1 Pa = 1 N / 1m2
Pressure depends on twofactors 1.force(thrust)-more force more pressure 2.area -more area less pressure
“The same force produces lesspressure if it acts on a largearea but can produce lesspressure if acts on a smallarea.”
every day observation 1.School bags have wide straps so the weight of bag may fall over a large area of the shoulder of the student producing less pressure on shoulder.
Sharp knife cuts better than ablunt knife so the force of ourhand falls over a very small areaof object produces large pressure.
The tractor have broad tyresso there is less pressure on groundand do not sinking tocomparatively soft field.
It is easier to walk on softsand if we have flat shoesrather than shoes with sharpheels.
The foundations of buildingsand dams are laid on a largerarea to produce less pressure
>The wooden or concrete sleepers are keptbelow the railway line. >A wide belt is provided over the wheels of an army tank.
Now answer Define thrust. What is its unit? What is the relation between pressure, force and area? Name the quantity whose one of the unit is Pascal (Pa)? Why does a sharp knife cut objects more effectively than a blunt knife? Why the tip of sewing needle is sharp? Why snow shoes stop you from sinking into snow?