Question
A bullet fired into a very thick wall loses one fourth of its velocity after penetrating 4m. How much further will it penetrate?
Solution
Let, u be the velcoity with which the bullet enters the wall.
At A and after penetrating AB = 4m, it loses one fourth of its velocity, therefore its velocity at B reduces to vB = 3u/4.
Let further it travel BC = x to come to rest.
Let a be the retardation offered by the wall.
For motion of AB:
Using third equation of motion,
v2 - u2 = 2as
For motion of BC:
Again using third equation of motion,
v2 - u2 = 2as
Dividing (2) by (1), we get
The distance of penetration,
At A and after penetrating AB = 4m, it loses one fourth of its velocity, therefore its velocity at B reduces to vB = 3u/4.
Let further it travel BC = x to come to rest.
Let a be the retardation offered by the wall.
For motion of AB:
Using third equation of motion,
v2 - u2 = 2as
For motion of BC:
Again using third equation of motion,
v2 - u2 = 2as
Dividing (2) by (1), we get
The distance of penetration,
