9. FRICTION

9. FRICTION

  • 9

    Friction

    Friction is a force that opposes the motion between two surfaces in contact, influenced by surface roughness and the force pressing them together.

  • 9.1

    Force Of Friction

    This section introduces the concept of friction, explaining how it opposes motion and factors that affect it.

  • 9.1.1

    Activity 9.1

    This section introduces the concept of friction, explaining its role in opposing motion and its dependence on surface characteristics.

  • 9.2

    Factors Affecting Friction

    This section explores the factors that influence friction, including surface texture and applied force.

  • 9.2.1

    Activity 9.2

    The section discusses factors affecting friction, exploring how different surfaces influence the force of friction experienced by objects.

  • 9.2.2

    Spring Balance

    This section explains the concept of friction and introduces spring balances as tools to measure forces.

  • 9.2.3

    Activity 9.3

    This section discusses the role of friction and how different surfaces affect motion.

  • 9.3

    Friction: A Necessary Evil

    This section discusses the dual nature of friction as both a necessary force for movement and a source of challenges in daily activities.

  • 9.4

    Increasing And Reducing Friction

    This section explores the importance of friction in various contexts, including how to increase or decrease it based on specific needs.

  • 9.4.1

    Activity 9.4

    This section explores how the application of different forces affects the movement of objects on various surfaces.

  • 9.5

    Wheels Reduce Friction

    This section explains how wheels reduce friction compared to sliding, highlighting the significance of rolling friction in everyday objects and machinery.

  • 9.6

    Fluid Friction

    Fluid friction is the resistance experienced by objects moving through gases and liquids, affecting their motion and energy.

  • 9.7

    Keywords

    This section outlines key terms related to the principles of friction, including various types and factors influencing frictional force.

  • 9.8

    What You Have Learnt

    This section encapsulates key learning points about friction, its types, factors affecting it, and its importance in everyday life.

  • 9.9

    Exercises

    This section provides exercises aimed at reinforcing the concepts of friction, its types, and the factors affecting it.

  • 9.10

    Extended Learning — Activities And Projects

    This section discusses various activities and projects related to friction.

    • Key Summary

    Friction is a force that opposes the relative motion between two surfaces in contact. It plays an essential role in various daily activities and applications, as it can both facilitate movement and hinder it depending on context. Understanding the factors affecting friction, its types, and how it can be increased or reduced is crucial in numerous fields, from sports to engineering.

    Key Takeaways

    • Friction opposes the relative motion between two surfaces in contact.
    • Friction depends on the nature and smoothness of the surfaces.
    • Static friction is greater than sliding friction.

    Key Concepts

    • Friction: A force that opposes the relative motion between two surfaces in contact.
    • Static Friction: The frictional force that must be overcome to initiate the movement of an object at rest.
    • Sliding Friction: The frictional force acting when an object is already in motion over another surface.
    • Rolling Friction: The resistance encountered when an object rolls over a surface, generally less than sliding friction.
    • Fluid Friction: The frictional force exerted by gases and liquids acting on objects moving through them.
    • Lubricants: Substances used to reduce friction between surfaces, allowing for smoother motion.
    • Drag: The frictional force acting on an object moving through a fluid.