Question

why is a sharp knife more effective in cutting a fruit than a blunt knife

Answer 1

because in a sharp knife area is less so we need less force to apply and pressure is large so it gets easier

Answer 2

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.