Question

Define Stress? And what are the units of Stress and Name 3 types of Stress!

Answer 1

Hi Sister,

Here is your answer,

What is Stress?

When a body is strained by external applied forces,internal forces of reaction come into play due to relative displacement of it's various parts which not only oppose the change but also tend to restore the body to it's original condition. These reactions set up within the body are equal and opposite to the applied forces ( according to Newton's third Law), so long as there is no permanent deformation on the body. The restoring force per unit are is called Stress. The component of the stress acting normally to any section. When the force applied is uniform, stress is obtained by dividing the total force area over which it acts.

       → Stress = force/area

       → The unit is pascal 

       → Its dimensional formula is the same as that pressure, ML⁻¹ T⁻²


 UNITS:- IN C.G.S SYSTEM THE UNIT FOR STRESS IS ''dyne cm⁻²

 IN SI SYSTEM THE UNIT FOR STRESS IS ''Nm⁻² OR PASCAL(Pa)


Stress is not a vector quantity. Stress is one of a class of Physical quantities called tensors.

There are three types of stress namely:-

1. Normal stress or longitudinal stress

2. Tangential or shearing stress

3. Volume stress or Bulk Stress

Normal stress:- The restoring force acting per unit area of cross-section to increase it's length is called normal or longitudinal stress.

Tangential stress or Shearing stress:- The restoring force acting parallel to the surface of the body per unit area is called Tangential Stress.

Volume stress or Bulk stress:- Hydrostatic pressure ( force per unit area) applied on the body is called volume or bulk stress.

If the volume of the body changes due to the change in pressure (DELTA) P without change in shape then volume stress= (Delta) P.



Hope it helps you !