📘 Concept Builder Notes: Friction – A Necessary Evil?
🔍 What is Friction?
Friction is a force that opposes the motion of an object. It acts when two surfaces are in contact and try to slide past one another.
📌 Why is Friction Called a Necessary Evil?
Friction is helpful because it allows us to walk, write, grip objects, and drive vehicles. However, it also causes wear and tear in machines, loss of energy as heat, and reduces efficiency. That's why it’s termed a "necessary evil".
📋 Types of Friction
- Static Friction: Prevents motion when a force is applied.
- Sliding Friction: Acts when an object slides over another.
- Rolling Friction: Occurs when an object rolls on a surface.
- Fluid Friction: Resists motion in liquids and gases (drag).
⚙️ Factors Affecting Friction
- Nature of the surfaces in contact (smooth or rough).
- Normal force (heavier objects have more friction).
- Area of contact (mostly negligible in solids).
📉 How Can We Reduce Friction?
- Using lubricants like oil and grease.
- Polishing surfaces to make them smoother.
- Using ball bearings and air cushions.
🧠 Real-Life Examples of Friction
- Shoes grip the ground due to friction.
- Brake pads stop a car using friction.
- Matches ignite due to frictional heat.
