Question

why do tools meant for cutting always have sharp edges??

Answer 1

they have sharp edge because they have to cut some thing , and for that they require maximum force and minimum area so that the pressure is more . that us why a sharp knife cuts better than a blunt knife

Answer 2

the cutting edge of tools like blade knife etc are provided with sharp edges to cut the things easily as the sharp edges has small Area on which the force is applied hence more pressure is applied