JFK - 3 shooters 6 shots

[profmunkin]

Profmunkin, I would really like an answer to my question.

Assuming you have not been unlucky enough to actually witness a live human being shot through the head with a rifle, how do you know what should happen? Why do you consider your expectations to be more reliable than the doctors, physicists, forensic technicians and other researchers who actually study this sort of thing as a profession?

I really want you to answer this question. Thank you.

How much force is there in a bullet?

[Jason Thompson]

While you were watching these exercises, did you notice separate sounds from the bullet shock, muzzle blast and target impact (assuming these were supersonic rifle bullets)?

I wasn't watching the exercise as such, and I am not sure even if they were firing live or blank rounds, or what the target was. The fort is not an operational military installation but a local tourist attraction, but they do still run military exhibitions. This was almost certainly members of the public being invited to shoot rifles under close supervision. I was walking past the fort, which entails walking around two sides of the grounds. One side is walking down on a level below the fort (approximately equivalent in my estimation to six floors of a building, coincidentally), the other side walks up the hill to the level of the fort shooting exercise. There are a number of buildings on the lower level interposed between me and the fort, and a number of buildings on the other side of the road as I walked up the hill. I didn't take too much note of the exact character of the sound, and there were a number of minor echoes, but I do remember it seeming to come from different places depending on where I was in relation to the shooter and other buildings, and even when i had a direct line of sight (and hearing) to the person I could see firing the rifle, I could sometimes hear the sound coming from somewhere other than directly in front of me.

[Jason Thompson]

How much force is there in a bullet?

That would be physics. Are we to assume you will ignore it anyway?

You believe a bullet will throw someone or something back on impact. We have already told you ad infinitum that that is NOT what bullets do, but you just will not accept it, will you?

[profmunkin]

Back to the WC

Always wondered about this, but I have not located an answer, that is James Tague, is nicked by flying cement that was gouged away from the curb by one of the snipers bullets.
Law enforcement was informed about this event within minutes after the assassination.

It was accepted that Tague had been effected by 1 of the 3 sniper bullets (one that missed).
Where is this documented by police?
Where is the laboratory report on the bullet residue on the cement, tests would assure this bullet was similar to the bullets found on the gurney and in the rifle?
Where are the official pictures of the mark the bullet had made in the cement?
Is there a direction to the mark, is so, what is the direction?
Why wasn't this portion of the curb preserved?

[ka9q]

How much force is there in a bullet?

That's not an answer to my question.

Your question doesn't even make sense. The following measurements of a bullet at an instant in flight, using SI units, do make sense. Note that "force" is not one of them:

0. The position of the bullet in three dimensions.

1. The mass of the bullet, measured in kilograms;

2. The velocity of the bullet. This is a vector indicating the bullet's direction of travel, with a magnitude (also known as the
speed) measured in meters per second;

3. The angular momentum vector of the bullet, i.e., the bullet's spin, measured in kilogram-meter²/sec;

4. The orientation of the bullet, i.e., whether it's flying straight, sideways or backwards, measured as three angles in degrees or radians.

An important value that can be computed from the above is the bullet's momentum. This is a 3-dimensional vector with units of mass times velocity, e.g., kilogram-meter/sec, parallel to the velocity vector of course.

One half the mass of the bullet times its speed squared gives the bullet's energy: E = 1/2 m v². This is a scalar quantity (i.e., it is not a vector and does not have a direction). Energy is measured in joules, also known as watt-seconds.

A bullet in flight exerts only a tiny drag force on the air in front of it. That's why it doesn't slow down much. When it hits a target, it rapidly slows down and exerts a force that depends on the mass of the bullet and the rate at which it is decelerated according to Newton's second law of motion: F=ma. This in turn depends on the bullet's velocity and the composition of the target. If the force exceeds the compressive strength of the bullet, it will begin to deform and possibly break apart. Otherwise it will remain intact.

So your question "what is the force of a bullet" has no meaning unless you give all those other numbers and tell us something about the target it is hitting.

[profmunkin]

How much force is there in a bullet?

That would be physics. Are we to assume you will ignore it anyway?

You believe a bullet will throw someone or something back on impact. We have already told you ad infinitum that that is NOT what bullets do, but you just will not accept it, will you?

How much force is there in a similar 6.5 mm bullet fired from this rifle?
please put it in some easy laymans terms for me - thanks

[profmunkin]

from Wiki
10.5 g (162 gr) RN 700 m/s (2,300 ft/s) 2,572 J (1,897 ft·lbf)
10.5 g (162 gr) RN 661 m/s (2,170 ft/s) 2,293 J (1,691 ft·lbf)

Or if you pressed the rifle stock up to the side of your head, and pulled the trigger, the recoil would most likely render you unconscious as your head was being propelled away from the rifle.

Yes most certainly your body or head moves in proportion to how much energy is absorbed or transferred from the bullet.

[ka9q]

How much force is there in a bullet?

If you are asking about a bullet's ability to "shove" its target, then you are interested in its momentum. I just described what momentum is: mass times velocity. The Carcano fired a 160 grain (10.37 gram) bullet at a muzzle velocity of about 2,000 feet/sec (610 meters/sec). Its muzzle momentum is therefore 6.32 kg m/s, and a little less when it reached JFK.

The importance of momentum is that it is always conserved in any interaction (like a collision). So when a bullet hits a target, the combined momentum of the bullet and target must be the same as their combined momentum before impact.

A human head weighs about 5 kg. For the moment let's ignore the fact that it's attached to the body by a neck; this is valid for small movements of the head when the neck muscles are not tensed. Assume a Carcano bullet embeds itself in a stationary 5 kg head; no bullet fragments exit. The momentum of the incoming bullet was 6.32 kg m/s, so the combined momentum of the bullet and head after impact must also be 6.32 kg m/s. The velocity of the head, moving by itself without any restoring force from the neck, will then be 6.32 kg m/sec / (5 + .01) kg = 1.26 m/sec.

That's not very fast at all, about the speed of a vigorous nod. And that's just the head alone, not the whole body.

If any fragments of the bullet do emerge, as they did from JFK's head, they will carry out some of the bullet's original momentum instead of transferring it to the head, so the head will move even more slowly. The effect of the neck muscles will also act to reduce the head motion. Indeed, we see that JFK's head does jerk forward a few inches between Z312 and Z313. This is exactly the motion we would expect to see as the bullet hits him from behind.

Now let's consider the effect of a bullet on the body as a whole. If the entire body has a mass of 75 kg, then shooting it (anywhere, not necessarily the head) with a Carcano will impart a velocity to the whole body of only 6.32 / 75 = .084 m/sec (84 mm/sec).

Again this very slow velocity is an absolute maximum that assumes the bullet comes to rest inside the body, transferring all its momentum. If any bullet fragments emerge, their momentum will not have been transferred to the body and it will move even more slowly. We're also ignoring any other external forces on the body; if the victim is sitting in a limousine seat, friction from the seat and arm rests will also tend to keep the body from moving.

You can see from all this that a bullet simply cannot blow its victim's entire body violently backward, as seen so often in Hollywood movies (where it is in fact faked). The back-and-to-the-left motion of JFK's body seen in the Zapruder film could not possibly have been caused by a bullet pushing on his head from the front. His motion had an entirely different cause, namely the sudden contraction of every muscle in his body when the bullet (from behind) destroyed his brain and sent massive neural impulses down his spinal cord. The stronger back and leg muscles dominated, resulting in the motion we see.

[Jason Thompson]

Yes most certainly your body or head moves in proportion to how much energy is absorbed or transferred from the bullet.

Yes, it does. The question is how much of that energy is absorbed or transferred, and how much is transferred to moving the target rather than simply breaking through it? Bullets are designed to penetrate.

Another bit of physics you won't believe, I'm sure, but you can be hit with a large slow moving object or a small fast moving object, and both can have the same kinetic energy or momentum, and both can have VERY different effects when they hit you due to their size and shape. Hold your hand flat on a wooden surface and hit it with a hammer and it will hurt. Try it with a nail between the hammer and your hand and you'll nail your hand to the wood, despite the same momentum and energy being involved in hitting it with the hammer.

Yes, if you put the stock of the rifle against your head and fired it, the force of the recoil would propel your head, but the stock is a large, flat, wooden area pressed against your head and moving at a significantly lower speed than the bullet, not a small, pointed metal object at extreme speed.

And again I will point out that there are countless experiments involving the effect of bullets hitting various things, not to mention reams of film from wars and the like showing people being shot, and one thing they all have in common is that the bullets do NOT shove their targets on impact to any singificant degree. They punch right through them. That is, after all, what a bullet is supposed to do.

[ka9q]

Yes most certainly your body or head moves in proportion to how much energy is absorbed or transferred from the bullet.

Not energy, but momentum. They're two different things.

Energy and momentum are both conserved quantities; they cannot be created or destroyed. But energy can also be converted into different forms, notably heat. When a bullet hits a target, much of its kinetic energy (energy of motion) is spent deforming the bullet and disrupting the target. All this energy eventually ends up as heat.

Momentum, unlike energy, cannot be converted to another form. It can only be transferred from one object to another. No matter what happens in the collision between a bullet and its target, the total momentum of bullet and target will be exactly the same, before and after.

So if you are interested in how much a target will move when hit by a bullet, you need to know the bullet's mass and momentum and the mass of the target. (Since the bullet usually has a much smaller mass than the target, you can disregard the bullet's mass in most cases.) Most of the bullet's kinetic energy is converted to heat, but a little kinetic energy remains in the (slow) residual motion of the target (and bullet fragments) necessary to conserve momentum.

[Chew]

from Wiki
10.5 g (162 gr) RN 700 m/s (2,300 ft/s) 2,572 J (1,897 ft·lbf)
10.5 g (162 gr) RN 661 m/s (2,170 ft/s) 2,293 J (1,691 ft·lbf)

Or if you pressed the rifle stock up to the side of your head, and pulled the trigger, the recoil would most likely render you unconscious as your head was being propelled away from the rifle.

You are neglecting the contribution of the powder to the recoil. The MC used 30 grains of powder that was expelled at ~4600 ft/sec. This means the momentum applied to the shooter by the recoil is always greater than that applied to the target by the bullet.

[ka9q]

And again I will point out that there are countless experiments involving the effect of bullets hitting various things, not to mention reams of film from wars and the like showing people being shot, and one thing they all have in common is that the bullets do NOT shove their targets on impact to any singificant degree. They punch right through them. That is, after all, what a bullet is supposed to do.

As demonstrated by the Mythbusters numerous times. Even a large .50 caliber sniper rifle barely moved its target.

Different bullets are designed to do different things. Metal-jacketed military bullets (required by international treaties) often do punch through their targets, though they will still disintegrate when they hit bone at sufficiently high velocity. We saw both effects in the JFK assassination; Oswald's second bullet (CE399) did not disintegrate because it first punched through JFK's neck, losing energy without hitting any bone. Then it hit Connally in the back, doing considerable damage to his thorax and breaking a rib but not shattering the bullet because it had already lost too much energy. It then continued through his wrist, again breaking a bone (the radius) while only flattening the bullet. Oswald's third bullet, however, hit JFK's skull at full velocity. The hard bone impact decelerated the bullet quickly enough to immediately deform and fragment it.

Hunters prefer non-jacketed soft lead bullets designed to deform very easily even when they only hit soft tissue, fragmenting and releasing their energy much more quickly than a jacketed bullet. This greatly increases lethality, lessening the risk that the animal will linger and suffer, and it also reduces the risk to other hunters from a bullet that punches through its target with much of its original energy left.

[Philthy]

I've gone deer hunting using a 12 gauge shotgun, with slugs as the ammunition. I could hear the "THUMP" of the slug hitting the deer. By the time the slug hits the deer, the sound of the shot is dissipated.

If you press a rifle to to your forehead, it's highly unlikely it would "knock you out." The recoil would shove your head back. This is why, when firing, you hold the weapon snugly to your shoulder, so it doesn't come back and pound the hell out of your shoulder. Also, never, ever brace your shoulder between aimmovablele object and then shoot. severelylbruiseded or broken shoulder will be the outcome.

Phil

[profmunkin]

Yes most certainly your body or head moves in proportion to how much energy is absorbed or transferred from the bullet.

Yes, it does. The question is how much of that energy is absorbed or transferred, and how much is transferred to moving the target rather than simply breaking through it? Bullets are designed to penetrate.

Another bit of physics you won't believe, I'm sure, but you can be hit with a large slow moving object or a small fast moving object, and both can have the same kinetic energy or momentum, and both can have VERY different effects when they hit you due to their size and shape. Hold your hand flat on a wooden surface and hit it with a hammer and it will hurt. Try it with a nail between the hammer and your hand and you'll nail your hand to the wood, despite the same momentum and energy being involved in hitting it with the hammer.

Yes, if you put the stock of the rifle against your head and fired it, the force of the recoil would propel your head, but the stock is a large, flat, wooden area pressed against your head and moving at a significantly lower speed than the bullet, not a small, pointed metal object at extreme speed.

And again I will point out that there are countless experiments involving the effect of bullets hitting various things, not to mention reams of film from wars and the like showing people being shot, and one thing they all have in common is that the bullets do NOT shove their targets on impact to any singificant degree. They punch right through them. That is, after all, what a bullet is supposed to do.

The answer should be equal effect, if all of the bullets momentum is transferred to the head.

Were did you see the videos of unconcious people with their heads hanging free getting shot in the head with a high powered rifle?
Please post the url.

[profmunkin]

I've gone deer hunting using a 12 gauge shotgun, with slugs as the ammunition. I could hear the "THUMP" of the slug hitting the deer. By the time the slug hits the deer, the sound of the shot is dissipated.

If you press a rifle to to your forehead, it's highly unlikely it would "knock you out." The recoil would shove your head back. This is why, when firing, you hold the weapon snugly to your shoulder, so it doesn't come back and pound the hell out of your shoulder. Also, never, ever brace your shoulder between aimmovablele object and then shoot. severelylbruiseded or broken shoulder will be the outcome.

Phil

Your probably correct, so for this experiment lets hold the gun an inch or so away from your head, lets let it get a little momentum built up before it knocks you sensless.