Question

A Bullet moving with a velocity 200cm/s penetrates a wooden block and comes to rest after traversing 4cm inside it.
What velocity is needed for travelling a distance at 9cm in same block?

Answer 1

using
v^2-u^2=2as
v=0
u=200

40000=2*4*a
5000=a

s=9

then
u=0
v=?
a=5000
so
v^2=2*5000*9
v=300cm/s

Answer 2

Answer:

v^2-u^2=2as

v=0  u=200

40000=2*4*a

5000=a

s=9

then

u=0  v=?  a=5000

so ,

v^2=2*5000*9

v=300cm/s