: Ok basically a sharp knife can cut something better than a blunt knife because it has a higher pressure. Pressure is the force applied per unit area. That means the pressure will be directly proportional to force and inversely proportional to area. Now, we applied the same amount of force on both the knives. Then, why was the result different? This is because the area on which the force acted was different. In the case of a blunt knife, the cutting edge is thicker. That means, the area is larger. As a result, the force of our hand falls over a larger area of the knife, producing lesser pressure. Hence, it is difficult to cut with a blunt knife.