Resistive force from bullet penetrating wood

[Jjolly65]

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 I am wrong... Am I missing something?

 

[Chewy0087]

F = ma

Wood exerts 5516.6785 on the bullet like you said, work out the bullets deceleration then try SUVAT

 

[LowlyPion]

You found the force by figuring the acceleration.

t = v/a

That's true. But unfortunately it's not = v / F

 

[HussanAli]

WoW the rifle is too big. LOL