Which type of friction occurs when two surfaces first begin to slide over each other?

The type of friction that occurs when two surfaces first begin to slide over each other is known as static friction. However, in the context of common terminology in physics and mechanics, the term "starting friction" aligns with static friction. This is the force that must be overcome to initiate the sliding motion between two surfaces that are at rest relative to each other.

Static friction acts to prevent motion until a sufficient force is applied. Once this force exceeds the maximum static friction force, the surfaces then transition to sliding over one another, at which point sliding (or kinetic) friction becomes relevant. The understanding of this friction is critical in various applications, especially in lineman work, where safety relies on knowing how to manage and anticipate frictional forces.

While terms like rolling friction refer to the resistance encountered when an object rolls over a surface, sliding friction pertains to the resistance during sliding once motion has started. Dynamic friction is typically associated with the forces at play during continuous motion, not the initiation of movement. Understanding these nuances helps in properly identifying and addressing friction in practical scenarios.