What is static equilibrium in machines?

Static equilibrium refers to a condition in which a system is at rest and all the forces and torques acting upon it are balanced, resulting in a net force and a net torque of zero. This means that the sum of all forces in any direction is equal to zero, and the sum of all torques about any point is also equal to zero. In practical terms, for an object in static equilibrium, it will not accelerate or rotate; it will remain in its current position until acted upon by an external force.

This concept is crucial in understanding how machines and structures maintain stability and perform effectively without collapsing or failing under various loads. When all forces are perfectly balanced, it ensures that the machine functions correctly without unwanted movement or deformation, which is fundamental in engineering applications.

The other options misinterpret the nature of static equilibrium. Only considering forces in motion, implying that one force is dominant, or applying the concept solely to dynamic systems does not align with the principle of static equilibrium, which is strictly concerned with the balance of forces in a non-moving scenario.