2.4.3 FrictionThe most widely used model for friction is the Coulomb model, developed in the 18thcentury by Charles Coulomb (1736-1806). The Coulomb model is an approximation toreal friction, but models it well for most common applications. The Coulomb model splitsfriction into two categories: static and dynamic. Coulomb observed that there is a certainamount of force that must be applied to an object before it will begin to move. Before thisforce is reached, friction will keep the object in equilibrium by equaling the force put onthe object: this is known as static friction. Dynamic friction arises when the force hasexceeded the maximum static friction force and the object begins to move