Skychief said:
It's a wonder to me that a bullet (ball) is considered to have hit with less energy than what the ballistic tables calculate that energy to be simply because it passes through an animal.
If a ball at "X" velocity, and "Y" mass, has "Z" amount of energy at a given range, isn't a target at that range, struck with "Z" amount of energy regardless of where the projectile winds up?
If said projectile hits a Tyrannasaurus Rex (without an exit) or a pizza box (with an exit), hasn't it struck each with the same amount of energy???
I hope that you'll consider commenting on these thoughts as it appears that you're tiring of the thread. Maybe I'm missing something and would be pleased to know what, if I'm mistaken. Sincerely.
Best regards, Skychief
Great question. I started typing a reply earlier this morning, but it quickly got too complicated so this is my effort to give you a simple response and conserve some time. If need be I can expand.
Think about a marathon runner who breaks through a ribbon as he crosses the finish line. Now replace that paper ribbon with a steel cable and imagine the result.
In both cases the runner has the same amount of kinetic energy, so why can the runner break through the paper ribbon with no consequence, but he would be stopped and severely injured by the cable?
The answer comes from Newton's Third Law: for every action, there is a reaction.
When the runner runs into the cable, he is exerting a force on it. The cable reacts back with the same amount of force. Because the cable is strong, it can take a lot of force before it breaks, so it is able to react to the full force of the runner, causing him to stop (and be injured). In other words, the cable stops the runner by applying a force on the runner. The source of the force came from the runner himself who first acted on the cable. But because to every force there is a reaction, the cable reacted by matching the force that the runner applied to it.
Back to the paper ribbon. The paper ribbon is not strong enough to react to the full force of the runner. Instead the ribbon breaks at a force much lesser. The runner keeps on going, maintaining most of his energy. He only imparted a small force (or energy) to the paper because that's all the paper could take until it reach its limit and broke. The ribbon did not stop him, because it did not react with the same force, so the runner was left passing through and maintaining most of his energy.
Now it's the same thing with a paper target. The paper can only provide a little resistance to the bullet before it tears. When this happens, the bullet keeps on going with most of its energy. The only energy the paper took from the bullet was the amount needed to tear a hole in the paper. The bullet did NOT exert all of its energy onto the paper, because the paper could not provide an equal reaction.
Does that make sense?
To get back to our exit wound scenario, any object that is in motion has kinetic energy. The bullet gets this energy from the explosion of the gun powder. For a bullet to do the most damage to an animal, you want the bullet to transfer as much of that explosion to the animal as possible.
If the bullet goes through thin flesh that does not have the ability to resist or react to the force of the bullet (like our paper ribbon), the bullet will break through and keep going, maintaining much of its energy. But if you hit say a bone that is able to react by stopping the ball completely, it absorbed all of the energy from that explosion and probably ended up annihilated, like our runner who ran into the cable (or in this case a brick wall).
To LD's point, this collision would in fact distort the ball which would change how it behaves from that point on, but the energy transfer principal is still the same.
In general, the more energy from that gun powder explosion you can transfer to the animal, the more destructive the result will be.
