Question

why does a bullet fired on a windowpane makes a clean hole in it whereas a peeble striking the same glass smashed it into pieces​

Answer 1

Explanation:

so the thing is that pressure is defined as the force exerted per unit area. if area in contact is small, pressure will be large and vice versa if area is large.

therefore since a bullet has a very small area of contact the pressure will be very large causing a hole but if a large thing smashes in then pressure will be less but the energy will spread all over the area which might cause the glass to break into pieces.