Why does a knife need to be pulled back and forth to cut things?

Question

Like what difference does the cutting motion do compared to just pushing down a knife ?

In: Physics

Answer 1

Depends on the knife. If it has one sharp edge, use it both directions. If it has teeth. there is a difference. They are not symmetrical. Some are made to be pulled, and others are pushed. An extreme example is a chainsaw. It only works in one direction.