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Time of Bullet

  • Thread starter Jjolly65
  • Start date
  • #1
3
0

Homework Statement




A rifle with a barrel length of 50.86 cm fires a 7.06 g bullet with a horizontal speed of 449 m/s. The bullet strikes a block of wood and penetrates to a depth of 12.9 cm.


What resistive force (assumed to be constant) does the wood exert on the bullet?
5516.6785 N


The Attempt at a Solution



How long does it take the bullet to come to rest?
Shouldn't it just be t = v/a t = 449/ 5516.6785 = 8.14*10-2
Thats what I'm getting but its saying im wrong... Am I missing something?
 

Answers and Replies

  • #2
370
0
F = ma

Wood exerts 5516.6785 on the bullet like you said, work out the bullets deceleration then try SUVAT
 
  • #3
LowlyPion
Homework Helper
3,090
4
You found the force by figuring the acceleration.

t = v/a

That's true. But unfortunately it's not = v / F
 
  • #4
14
0
WoW the rifle is too big. LOL
 

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