One of the most common questions in CBSE Science exams is: Why is friction called a necessary evil? The answer is simple—friction helps us in many ways, but it also causes problems. It is “necessary” because we cannot survive without it, but “evil” because it wastes energy.

Below is the detailed explanation for Class 8 students.

1. Understanding the Concept

To understand why is friction called a necessary evil, we must look at its dual nature. It acts like a friend when it helps us walk, but acts like a foe when it wears out our shoes.

2. Why is Friction “Necessary”? (The Good Side)

Friction is absolutely essential for our daily existence.

• Walking & Running: Without friction between our feet and the ground, we would slip and fall.
• Writing: The friction between the pen tip and paper allows ink to stick.
• Grip: Holding a glass of water is possible only because of friction.

3. Why is Friction an “Evil”? (The Bad Side)

On the other hand, friction causes significant loss.

• Wear and Tear: It damages machine parts, tires, and shoe soles.
• Heat Production: Rubbing your palms together creates heat. In machines, this heat wastes energy.
• Slows Down Motion: It opposes movement, meaning we need more fuel to keep cars moving.

Conclusion: In short, we cannot eliminate friction because we need it to function, but we must also control it to reduce damage. This balance between its usefulness and its harmful effects is exactly why is friction called a necessary evil in physics.

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