For a system to be in equilibrium, several important criteria must be satisfied, depending on the context (e.g., mechanical, thermal, chemical). Here are the general criteria for mechanical and thermodynamic equilibrium:
### Mechanical Equilibrium
1. **Translational Equilibrium**: The net force acting on the system must be zero. Mathematically, this is expressed as:
\[
\sum F = 0
\]
2. **Rotational Equilibrium**: The net torque acting