What is one of the four laws that govern the behavior of friction?

One of the fundamental laws that govern the behavior of friction is that sliding and limiting friction are proportional to the normal force acting between the two surfaces in contact. This relationship indicates that as the normal force increases, so does the frictional force. It is a key concept in understanding how friction operates in various mechanical systems, contributing to the stability and motion of objects.

In practical terms, this means that heavier objects, which exert a greater normal force, will experience more friction than lighter objects under the same conditions. This principle is critical in applications ranging from the design of braking systems to the analysis of tire performance on different road surfaces. Understanding this law helps engineers and technicians predict how machines and structures will interact with their environments, ensuring safety and efficiency.