[model49]

Any gunshot with the force required to knock a person down would also knock down the person firing the shot.

In a perfect situation - yes.

If the two people involved were exactly the same size and neither were prepared for the recoil or impact.

Theoretically it would happen just like those little kinetic toys that are so popular on desks. But there are too many variables to deal with in real life.

Did the projectile hit bone or did it carry all the way through? Did both parties have good footing?

How do people operate jack hammers without being killed?

m49

 

[model49]

And I agree with everything that you and Demon say on this matter if it happens in a perfectly controlled situation.

m49

Sorry 49. Demon gets the physics award for this one. It's that Newtonian force forward/force backward/equal momentum thing.

Newton 3, To wit:

"For every action, there must be an equal and opposite reaction." Equal being the operative word, here...what it means is that the momentum of the bullet and the momentum of the gun are equal...at least hypothetically. They can never be precisely equal in the firing of a gun...because momentums can only be equal in the absence of outside force, or in the presence of equal outside force...but they'll be so close that there won't be any practical difference. In layman's terms: The bullet will strike with the same impact that the gun punches your hand...or actually just a bit less due to velocity and momentum loss on the way to the target...and only then if the entire momentum is transferred to the target...as with hitting a solid steel plate.

 

[model49]

....and you can stick your cartoons and smart-assed replies where the sun don't shine.

m49

http://encyclopediadramatica.com/Miracles

 

[model49]

...As in everything doesn't happen like the kinetic ball desk toys.

I agree that momentum is momentum - the effects of the momentum, for example trying to stick someone with a sewing needle and trying to stick someone with with the end of a baseball bat, using the same momentum, will have very different results.

Thank-you,

m49

Just to stir the pot a bit, I would like to point out that a point blank shot with a high velocity cartridge, that does not expand on impact, often results in a through and through wound.

This means that the potential force represented by the impact of the high speed (and heavy) round is ameliorated by the round passing through the target without dumping all of the kinetic energy.

There are a lot of other factors at work like hydrostatic shock, temporary wound cavitation etc etc, but the bottom line is that a through and through will never impart the same amount of force to an object as a shot whose impact is stopped by that target.

 

[model49]

That's not momentum, 49. That's the body's nervous reaction to pain and shock.

People who are shot...even by complete surprise...react differently. One will crumple up like a puppet with its strings cut, while another may pitch violently backward. A third may fall forward. Another may show no immediate reaction at all.

I understand where you're coming from on this. But say you used the needle/bat example on a corpse.

Would the results be the same?

Going with the block of steel example you gave, let's say the block of steel was 25# instead of 200#. Using 2 of these 25# blocks - one to take all of the recoil of the .44 mag revolver and the other to take the impact of the bullet are you saying that both blocks would react exactly the same when the gun was fired?

What if you used a 25# bag of sand for the recoil of the revolver and the steel block for the bullet...or vice versa?

I don't dispute any of Newton's laws but even though momentum is the same, the reaction to this momentum, not counting human pain and nervous reaction will differ according to the weight and mass of the objects the momentum transfers the energy to.

m49

 

[model49]

49...You're graspin' at straws. The physics doesn't support the theory.

Once the bullet has struck, the victim's physical reaction has nothing to do with impact momentum. If I stick you with a hot needle, I don't generate enough momentum to wiggle your hat. You may jump backward with enough force to stumble and fall...but momentum didn't do it. You did it with a separate action/reaction event set off by your muscle twitch...and the momentum that twitch produced carries you.

I asked you before and I'm trying to say that the impact will affect different objects different ways.

Go back to the question I asked you about using the needle and the bat to impact a corpse for example. Will the corpse react the same way to both impacts?

Momentumtum is Mass X Velocity. A 240-grain bullet inpacting at 1200 feet per second doesn't have enough momentum to move a 200-pound man's mass...even if it stopped on impact and delivered the full measure. That's the reality.

And what is the opposite physical reaction to the force of this impact of this reality? Is it exactly the same - let's say if a 60 lb. child pulled the trigger?

Momentum is momentum. The impact should be the same if using needle at 1200fps as using a baseball bat. The mass of the baseball bat will cause a different reaction to whatever it strikes opposed to the needle at the same 1200fps be it a block of steel, chunk of firewood or a dead or live human being.

To say that a shot from a firearm that would have enough recoil to knock the shooter down will always knock the target down or vice versa is a generalization that could not possibly hold true 100% of the time.

We're talking about a shooting here - not a laboratory experiment.

Your explanation of physics are exactly "on target". I'm not arguing those truths. Newton's laws are based on all things being equal. In most cases that is rare.

Thank-you for your patience and ability to carry on a discussion in a manner that I would expect from a gentleman. The peanut gallery could learn a lot from you.

m49

 

[model49]

Just taking a friendly jab at the abject failure that is Polky County schools. It seems to have affected the ability to understand that guns aren't exempt from physics.

Polk Co. schools teach us how to think, to take what's given us and use it to explore beyond what's been memorized solely to pass a test.

Maybe you'd better take a look at graduation rates between Polk Co. and Rutherford Co. before you make a bigger fool of yourself.

It's obvious, using you as an example, that Rutherford County schools teach their kids to be cowards and name callers hiding behind keyboards.

m49

 

[model49]

No disrespect here but you have just explained, in your own terms, what I have been saying all along.

That even though momentum is still the same on both ends, the objects that this momentum is imparted upon will react differently according to their size, weight, stability and/or mental conditioning.

Therefore it cannot be said that just because a firearm has the ability to knock down someone on one end that it will knock the person or object down on the other end as stated by the genius from one of the worst school systems in the state.

Thank-you again.

m49

Okay...Let's take a look at something that caught my attention. The part about the 60 pound child.

Momentum will be equal and conserved unless and until it encounters an outside force.

Or...An object in motion will remain in motion until it is forced to slow down or stop. Momentum is why. Momentum will be conserved forever in the absence of an outside force.

When you fire a gun, the bullet and the gun make up the system. Anything outside that system is considered to be an outside force. That includes the shooter. The shooter's mass determines how far and how quickly he will move when the gun recoils. You can fire a fairly light .223 caliber bolt-action rifle, and be moved very little. A 60-pound child can fire the same rifle and is moved backward. It works that way because you're both absorbing the full measure of momentum. Your body mass absorbs more of it than does the child's. So, he moves backward and you don't.

By the same token, if a 100-pound man fires a .600 Nitro Express rifle beside a 200-pound man...he will move farther from the recoil, but it will hurt the 200 pound man's shoulder more. The less massive shooter is rolling with the punch, and dissipating the force over a longer distance while the more massive shooter soaks it up. Again...Body mass is the variable.

The bullet's impact takes a little different form because it penetrates, and if it passes completely through...it can't deliver its full jolt because if it's still moving after it exits, it still has momentum left...so it couldn't have imparted all of it to the target. Even if the bullet doesn't pass through, the jolt that it delivers is spread over a longer time and distance instead of unloading all of it in an instant. Shoot a 75-pound steel plate standing on a pedestal, and it will fall over. Shoot a 75-pound hog cadaver, and it will barely move.

The more restive the target, the quicker the momentum is dumped. Shoot an empty plastic jug with a .44 magnum, and the movement is slight. Shoot the plastic jug filled with ballistic gelatin, and it gets more spectacular. A 200-pound man shot with a .44 Magnum will receive a harder jolt than a 60-pound child shot with the same round because he is more massive and more resistant. He soaks up more energy and momentum.

As I noted, a 200-pound man has 6,000 times the mass of a 240-grain lead bullet. Even if he were wearing a trauma plate that stopped the bullet cold...it still wouldn't have anough momentum to physically knock him down. I watched a trauma plate demonstration in which the recipients were shot at 25 feet with a .308 rifle. They didn't so much as stumble backward...and a .308 rifle completely outclasses the .44 in terms of energy and momentum, delivering over twice the thump at 100 yards than the .44 does at the muzzle.

 

[model49]

Now there was a good show on the history Channel last night that dealt with the invention of the Minie ball and how it influenced the Civil War.

If you want to talk about inertia and impact....how about an ounce of soft lead almost 1/2" in diameter coming at you.

That's bad stuff.

It changed almost everything we knew about warfare at the time.

m49

 

[model49]

That's when they started giving a little more thought to their ancient tactics of lining up across the field and shooting at each other. Seventy-five percent of the battlefield surgeons' work was amputations due to this projectile. Most victims only survived until gangrene set in.

m49

The results are in.

The .58 caliber rifled musket figured at approximately 100 yards...or about the average distance of a Civil War engagement.
This assumes the standard 60 grain FFG powder charge in a paper cartridge and the nominal MV of 960 fps.

.45 ACP figured at the muzzle with an average hardball velocity of 830 fps.

.58 caliber Minie' 490 grains at 700 fps impact velocity:

Energy 533 pounds feet
Momentum/PF 490

Taylor KO scale 28
****************

.45 ACP. 230 grains at 830 fps

Energy 351 pounds feet.
Momentum/PF 270

Taylor KO scale 12