**PRESSURE STRESS **

Pressure as a force which is perpendicular to the surface or we can that that the force which acts perpendicularly on the body and pressure is that thing which makes stress possible, we can say that stress is the property of the body which is under load and is related to the internal force.

stress is actually the property which is actually the reaction produced by the molecules of the body which is under some sort of action and which may result in making some sort of deformation, hence the easiest way to define stress is that it is the intensity of all additional forces which is produced per unit area.

## Pressure Conversion

**Some difference between pressure and stress. **

- The main difference between stress and pressure is that we can apply pressure in any direction but in order to apply pressure we have to apply force only in a perpendicular direction to this force.
- We can say that pressure is a force which acts externally and stress is the property which is applied internally and it is applied to the body in order to deform it.
- one of the most important differences between pressure and stress is that pressure is always compressive while stress can be compressive and in many situations, it can be tensile
- pressure is a scalar Quantity while the stress is a scalar Quantity and is it’s a tensor Quantity of the order 2
- the magnitude of pressure at any point is the same in all the possible direction and magnitude

**SI unit of pressure **

- The SI unit of pressure is Pascal and Pascal is defined as force per unit square meter. one Pascal pressure is one Newton per square meter and in addition to this Pascal is also described in terms of atm which is atmospheric pressure and in addition to one most frequently used denotation is torr and 1 atm = 101325 Pa = 760 torr

**SI unit of stress **

- stress is defined as force per unit area and it is the force which tends to cause the change in its shape and its even the SI unit of stress is also force per unit meter square, it is actually the average force per unit area which a particle of body exerts on any material, this is actually done on an imaginary surface then stress= force/area that is S=F/A

there are many situations in which you have to describe stress with a single number, in such situation all we have to do is to you single vector that you should have a number and a direction, according to this stresses are

- uniaxial normal stress, in this type of stress the stress leads to expansion to the material
- simple shear stress, this is normal stress in can be tensile or it can be an expansion
- isotropic normal stress

Here one thing to note is that the object can be one dimension or they can be two dimensions and they can be three dimensions and depending on the type of dimension stress changes.