Static friction is a type of frictional force that exists between two surfaces in contact with each other when there is no relative motion between them. It prevents the surfaces from sliding past each other when an external force is applied. Static friction acts in the direction opposite to the applied force, thus maintaining equilibrium and preventing motion.
The magnitude of static friction can vary and depends on several factors, including the nature of the surfaces in contact and the normal force pressing the surfaces together. The maximum value of static friction, known as the static frictional force, is given by:
F_static_max = μ_static * N
where F_static_max is the maximum static frictional force, μ_static is the coefficient of static friction, and N is the normal force exerted perpendicular to the surfaces in contact.
The coefficient of static friction, μ_static, is a dimensionless value that represents the interaction between the two surfaces. It depends on the nature of the surfaces and is typically determined through experimentation.
It's important to note that the static frictional force can vary up to its maximum value but will adjust to match the applied force until the force exceeds the maximum static frictional force. Once the applied force surpasses the maximum static frictional force, the surfaces will begin to slide, and kinetic friction takes over.