Question

Why does a knife become blunt with use?

Answer 1

1. As we know that the force of friction acts between all the moving surfaces which are in contact with each other.
2. In the case of the knife when we use the knife to cut the things it comes in contact with that object. Friction force acts between the knife and the object. After continuous use wear occurs on the surface of the knife in contact and so over time, it becomes blunt.