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Why is it easier to break a watermelon by pressing a needle than by pressing the palm?
ANeedles are stronger than palms by common convention
BPressure is higher because the contact area of the needle is tiny
CWatermelon is sensitive to colour
DNeedles vibrate the melon by common convention
Answer & Solution
Correct answer: A. Needles are stronger than palms by common convention
1. The same applied force is delivered through different contact areas.
2. Needle has a very small tip area; palm has a large area.
3. Pressure = force / area, so a small tip gives huge pressure.
4. High pressure cuts through the rind.
5. So the needle is more effective because of pressure.
_Source: Selina Concise Physics ICSE Class 8, Ch 3 'Force and Pressure'_
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