A body is said to be in equilibrium when the net forces acting on the body is balanced, net torque acting along the body is balanced and the temperature of the body is the same as that of the system it is a part of or its temperature it the same as the bodies in which it is in contact with. When a system is at equilibrium, nothing is changing. The sum of the forces and the sum or the torques is equal to zero.
Equilibrium is a state in which opposing forces or influences are balanced. There are many different types of equilibrium in physics. These include hydrostatic equilibrium, hyperbolic equilibrium point, mechanical equilibrium, radiative equilibrium, secular equilibrium and thermal equilibrium. Each specific type of equilibrium a different approach, however, the basic principle remains the same; all forces are balanced.