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Bullet hitting stationary Target.

  • Thread starter Adarshaero
  • Start date
  • #1
A bullet of 0.005 kg travelling at 20m/s penetrates deeply into a fixed target and is brought to rest in 0.01 sec. The distace through which it penetrates is:

I used,

acceleration= V/t
= 20/.01
a = 2000 m/sec sq

Distace covered = Ut+0.5 at^2
= 20*0.01+0.5*2000*(o.o1)^2
S= 30cm.

Is it correct or any other solution is possible..?
 

Answers and Replies

  • #2
1,955
252
The initial speed and the acceleration have opposite directions.
 
  • #3
@willem2:

How is tat? can you plz elaborate.
 
  • #4
gneill
Mentor
20,801
2,778
Does the bullet slow down or speed up as it moves through the block? So is acceleration positive or negative?
 
  • #5
Acceleration reduces as the bullet enters the target.
 
  • #6
so acceleration is negative......
 
  • #7
gneill
Mentor
20,801
2,778
so acceleration is negative......
The velocity reduces as it passes through the target. So yes, acceleration is negative (in the direction opposite to the velocity).
 
  • #8
I understand ur point. So is the approach right? And how about answer?
 
  • #9
gneill
Mentor
20,801
2,778
The approach is fine. How about the answer? Have you calculated one with the new knowledge about the acceleration direction?
 

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