What is the definition of limiting friction?

Limiting friction refers to the maximum frictional force that must be overcome for an object to begin moving from rest. This phenomenon occurs just before an object begins to slide over a surface. At this critical point, the frictional force reaches its highest value, which is why this maximum force is significant in determining how much force needs to be applied to initiate motion.

The concept of limiting friction is crucial in various practical applications, such as in machinery, transportation, and safety calculations. It is essentially the threshold where static friction transitions into kinetic friction, which is typically lower than the static (limiting) friction.

In contrast, the other provided options describe different forms of friction or aspects of motion that do not specifically characterize the threshold at which an object begins to move. For example, the friction experienced while an object is moving would pertain to kinetic friction, and the friction felt by a stationary object does not address the maximum force required to initiate movement. Further, friction experienced by an object in a fluid is relevant to fluid dynamics but does not directly address the concept of limiting friction as it applies to solid surfaces.