Static friction is a type of force that prevents two surfaces from moving when they are in contact with each other. It is caused by the irregularities on the surfaces that interlock and resist motion.
Static friction occurs when two surfaces are at rest, while kinetic friction occurs when the surfaces are in motion. The amount of force required to overcome static friction is usually greater than the force needed to maintain motion against kinetic friction.
The magnitude of static friction depends on the nature of the surfaces in contact, the force pressing the surfaces together, and the presence of any external forces acting on the system.
The coefficient of static friction can be calculated by dividing the maximum force of static friction by the normal force. This value is specific to the two surfaces in contact and is a dimensionless quantity.
The maximum force of static friction can be determined experimentally by gradually increasing the applied force until the object just begins to move. This force is equal to the magnitude of the static friction force and can be used to calculate the coefficient of static friction.