We all come under word Stress in our daily life when some external thing affects our state of mind. Similarly in physics Stress is the external restoring force acting per unit area.
Stress is denoted by $\sigma$
. It is expressed in N/m2.
Stress formula is given by
F = Force applied
A = Area on which force is acting.
Stress formula is used to find stress applied on any given body if force and area on which force is applied is given in the problem.