2. Force & Laws Of Motion
Thrust And Pressure
(A) Thrust :
The force acting normally on surface is called 'thrust'.
This is a vector quantity.
It is measured in newton (N).(B) Pressures :
The thrust on an unit area of a surface is called 'pressure'.Unit :
The SI unit of pressure is newton per meter square or N/m2
, other units of pressure are pascal and bar.
One Pascal : One pascal is defined as the pressure exerted on a surface area of 1m2
by a thrust of 1 newton.
i.e. 1 Pascal = 1 N/m2Some examples based on pressureExample.
Inserting a pointed nail in a wooden block is an easier task than to insert a rod inside a wooden block with the same force because the nail has a smaller area and thus it will experience more pressure even with the same force.Example.
A sharp knife cuts better than a blunt knife.Example.
While walking, a man exerts more pressure on the ground in comparison to when he is standing. Pressure in fluids
A substance that can flow is called a 'fluid'.
liquid and gases are considered as fluids