Question

what does a sharp knife cut objects more effectively than a blank knife

Answer 1

Because less surface area applies more pressure

Answer 2

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A sharp knife cuts objects better because due to its very thin edge, the force of our hand falls over a sharp small area of the object producing a large pressure. And this large pressure cuts the object easily. A blunt knife has a thicker edge and does not cut the object easily. The lesser pressure cuts the object with difficulty.