Friction terminology in engineering mechanics: The maximum frictional force that acts just when a body is about to start sliding over another surface is referred to as what?

Introduction / Context:
Frictional behavior transitions from static to kinetic as a body begins to move. The peak value attained by static friction immediately before motion begins is crucial for design of brakes, clutches, and anchorage systems.

Given Data / Assumptions:

• Dry contact between two solid surfaces.
• No lubrication or adhesion effects beyond the classical model.
• Body is on the verge of impending motion (just about to slide).

Concept / Approach:

Static friction adjusts up to a maximum called the limiting friction, F_lim = μ_s * N, where μ_s is the coefficient of static friction and N is the normal reaction. Once motion starts, kinetic (sliding) friction, typically smaller, acts. Rolling friction is a different phenomenon arising from deformation and contact hysteresis of rolling bodies.

Step-by-Step Solution:

Verification / Alternative check:

Experimental graphs of friction force vs. applied tangential load show a rising line up to a peak (limiting value), then a drop to a lower constant value for kinetic friction.

Why Other Options Are Wrong:

Sliding friction (a) acts after motion starts; rolling friction (b) pertains to rolling bodies; “None of these” (d) and “Static drag” (e) do not match standard terminology.

Common Pitfalls:

Confusing the peak static value with kinetic friction; assuming friction remains constant across regimes.

Final Answer:

Limiting friction