How does a bullet pierce a target ?

Two bullets P and Q, masses 10 and 20 g, are moving in the same direction towards a target with velocities of 20 and 10 m/s respectively. Which one of the bullets will pierce a greater distance through the target?

A stone breaks the window glass into pieces, while a bullet pierces through the same. Why?

A rifle with a muzzle velocity of 100m//s shoots a bullet at small target 30m away in the same horizontal line. How high above the traget must the gun be aimed so that the bullet will hit the target. (Hint: use small angle approximation.)

A rifle with a muzzle velcity of 100 ms^(-1) shots a bullet at a small target 30 m away in the same horizontal line. How much height above the target must the rifle be aimed so that the bullet will hit the taget ?

A bullet moving with a velocity of 30sqrt(2) ms^(-1) is fired into a fixed target. It penetrated into the target to the extent of s metres. If the same bullet is fired into a target of thickness (s)/(2) metres and of the same material with the same velocity, then the bullet comes out of the target with velocity

A bullet moving with a velocity of 30sqrt(2) ms^(-1) is fired into a fixed target. It penetrated into the target to the extent of s metres. If the same bullet is fired into a target of thickness (s)/(2) metres and of the same material with the same velocity, then the bullet comes out of the target with velocity