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Showing 1 question in Physics for Class 8. Tap a card to reveal the answer.
PhysicsForce and PressureeasyA sharp knife cuts better than a blunt one. Explain using the idea of pressure.
Reveal answer ↓
What it is
Pressure is how concentrated a force is - the same push on a smaller area presses much harder.
Answer
Pressure is the force acting on a unit area, P = F/A. A sharp knife has a very small area at its edge, so for the same force the pressure it exerts is much greater, and it cuts easily. A blunt knife has a larger edge area, so the same force produces less pressure and cuts poorly.
P = F / A
- •Pressure = force / area (P = F/A)
- •Smaller area -> greater pressure
- •Sharp edge = small area = high pressure
Why learn this
It explains sharp knives, nails, a camel's wide feet on sand, and why a thin bag strap hurts your shoulder.
💡 Memory trick
Same force, Smaller area = Stronger press - the three S's.