Question

give reason for it easy to cut with a sharp knife than a blunt knife​

Answer 1

if the knife is sharp, contact area with the material to be cut is less. If it is blunt, contact area will be more. hence for the given force, pressure is more with sharp knife and pressure is less with blunt knife. Hence sharp knife cut the material 

Answer 2

because because as blunt knife covers more but sharp knife covers smaller area the force will be more than blunt knife so it is cut