What characterizes static equilibrium?

Static equilibrium is characterized by a state where a body is not experiencing any net forces or net torques, which results in a stable condition. This specifically means that the body has zero velocity, indicating it is at rest, and zero acceleration, meaning that there are no changes occurring in its state of motion.

In static equilibrium, all forces acting upon the body are balanced, so the sum of the forces equals zero. Similarly, there are no unbalanced torques acting on the body, leading to an equilibrium in rotational motion as well. Therefore, a body under these conditions remains stationary and does not accelerate, thus fulfilling the criteria for static equilibrium completely.

The other options describe phenomena that do not fit the definition of static equilibrium. A body in motion with constant velocity is in dynamic equilibrium, not static, while a body that is rotating implies angular motion, which is inconsistent with the concept of being at rest in static equilibrium. Friction can be present in a system at static equilibrium, but it is not a defining characteristic of the state itself.