Static Friction

Static friction is the force that resists the initiation of sliding motion between two surfaces that are in contact and at rest relative to each other. It occurs when an object is at rest and a force is applied to it, but the object does not move.

Factors Affecting Static Friction

Static friction depends on the nature of the surfaces in contact and the amount of force pressing the surfaces together. The factors that affect static friction include:

• Nature of the surfaces: Rougher surfaces generally have higher static friction.
• Normal force: The force pressing the surfaces together affects the magnitude of static friction.

Calculating Static Friction

The maximum static friction force (F_{s max}) can be calculated using the equation:

F_{s max} = μ_s * N

Where:

• μ_s is the coefficient of static friction.
• N is the normal force.

Applications of Static Friction

Static friction is important in various everyday applications, such as:

• Walking without slipping.
• Preventing objects from sliding on surfaces.
• Launching vehicles from a standstill.

Study Guide Questions:

1. What is static friction?
2. What factors affect static friction?
3. How is the maximum static friction force calculated?
4. Provide examples of the applications of static friction in everyday life.