Force caused by a bullet in a bone

  • Context: Undergrad 
  • Thread starter Thread starter danielamartins
  • Start date Start date
  • Tags Tags
    Bullet Force
Click For Summary

Discussion Overview

The discussion revolves around calculating the force exerted by a bullet when it penetrates a bone, based on parameters such as the bullet's velocity, weight, and the thickness of the bone. The context includes theoretical modeling and practical application in creating an exercise related to ballistics and human anatomy.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant inquires about the possibility of calculating the force from a bullet impacting bone, given specific parameters.
  • Another participant suggests a model assuming constant deceleration of the bullet, using the bone's thickness as the distance traveled, and outlines a method to calculate time, deceleration, and ultimately force using Newton's second law.
  • A participant seeks clarification on how to calculate acceleration based on the change in velocity and time taken for that change.
  • Further elaboration is provided on calculating acceleration through an example, illustrating the relationship between distance, velocity, and time.
  • One participant expresses gratitude for the clarification and indicates intent to perform calculations, inviting feedback on their results.

Areas of Agreement / Disagreement

Participants generally agree on the feasibility of calculating the force using the proposed model, but there is no consensus on the complexity or accuracy of different models that could be applied.

Contextual Notes

The discussion does not resolve the potential limitations of the model, such as assumptions regarding constant deceleration and the effects of varying bullet dynamics upon impact.

danielamartins
Messages
9
Reaction score
0
Is it possible to calculate the force caused by a bullet in a bone, knowing the velocity of the bullet when fired, its weight, and the bone's thickness?
If so, could you explain it a bit?
I need to create a sort of exercise, so I wanted to do something involving a bullet and a body. Therefore, I could add some details/info if necessary...
 
Physics news on Phys.org
danielamartins said:
Is it possible to calculate the force caused by a bullet in a bone, knowing the velocity of the bullet when fired, its weight, and the bone's thickness?
If so, could you explain it a bit?
I need to create a sort of exercise, so I wanted to do something involving a bullet and a body. Therefore, I could add some details/info if necessary...

An easy model that will get results that are order-of-magnitude sensible is to assume that the bullet decelerates at a constant rate until it either comes to a stop or exits the other side at a slower speed.

Now the thickness of the bone gives you the distance traveled, the initial speed and assumption of constant deceleration gives you the average speed that distance is traversed, from that you get the time of passage and the deceleration. Now the mass of the bullet and ##F=ma## will see you home.

No doubt the forensic pathologists have waaaay more sophisticated models... But not necessarily the case that a more sophisticated and accurate model will produce any more insights.
 
Thanks, but how can I calculate the acceleration?
 
danielamartins said:
Thanks, but how can I calculate the acceleration?

You know the change in velocity and you can calculate the time over which that change happens. For example, if a projectile moving at 20 m/sec is brought to a stop over a distance of 1 meter...

Its average speed through that meter is 10 m/sec (average of 20 and 0, assuming constant deceleration) so it take .1 sec to cover that one meter. Because the speed goes from 20 m/sec to 0 m/sec in that .1 sec, so the deceleration is 200 m/sec2.
 
Oh thanks! I was making it more difficult than it actually is. I'll try to do all the calculations and then, I'll post them here. If u could take a look I would appreciate it ;)
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
5K
  • · Replies 23 ·
Replies
23
Views
4K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 34 ·
2
Replies
34
Views
5K
  • · Replies 29 ·
Replies
29
Views
3K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K