you want to put all of the attention on what you consider significant "forward" movement that you say takes place between two frames of the film (12/13) rather than the significant backward movement that takes place between nine frames of the film (13-22). This is what I have been saying from the start.
All of the attention on two frames? Um, perhaps you missed the skull x-rays posted above.
You appear to believe that a projectile traveling at least 2000 feet per second before hitting the bone of a human scull will propel the head and body of that person a very minor amount in the same direction in which it is traveling before propelling the head and body a very significant amount in the opposite direction in which it was traveling. That is simply not true.
I'm going to guess you haven't spent much time hunting or shooting generally. Your statement above starts with a number, which suggests you are going to do a calculation of some kind, and then you just state "That is simply not true" again, based on nothing other than your personal belief in what happens under those circumstances.
Straight up, what's the largest animal you ever shot with a rifle? Because you don't seem to have much of an idea how a body reacts to getting shot in real life.
A full metal jacket round is pointy. It goes through things. It doesn't expand and gouge out as much tissue as a soft point round. It does not transfer much, or even most, of its kinetic energy to the target, but mostly passes through the target. People get this idea of bodies being dramatically thrown back from being shot by watching movies and television shows, but that's not how it works in real life.
The momentum that is going to be imparted to anything by a bullet at the unlucky end of a shooting - even if ALL of the kinetic energy were transferred to the target - is exactly the amount of momentum that is imparted to the person firing the gun. That's a fundamental conservation law of physics. Yes, different times of guns and rounds have varying amount of kickback, but they don't throw people across rooms the way you see in the movies. When someone is shot in the head, they basically just drop dead. Their body doesn't go flying away from the direction of impact. A particularly gruesome and well known example is the street execution captured on film in Vietnam. But more people who've actually been hunting know that what usually happens when you shoot a deer is that it looks at you and runs for a while before bleeding out. It is not bowled over by being shot. If you get a clean kill, it just drops.
Your head is like a weight on top of a spring. JFK is seated in the car. A bullet impact to the upper back right of his head is not going to impart some kind of lever action that is going to lift his head and torso up out of the seat and fling his body forward out of the seat. A 10 gram bullet is not going to do that, even at 2000 fps. What you see in the Zapruder film at the point of impact is a slight forward deflection of his head - again with his chin already close to his chest - and then a rebound back.
What's hilarious is that you seem to now notice that, yes, his head does jerk forward, but you say that, after the bullet has already clearly passed through his head there is "significant backward movement that takes place between nine frames of the film". This backward movement - taking a half a second, and after the bullet has already proceeded out of his head - is what you believe to be the impact effect of a bullet traveling 2000 fps. On top of that, you ignore the more sudden an immediate forward movement at the point in time that impact clearly occurs.
Ballistic gelatin is used to perform tests of terminal ballistics, in part because it is similar to body tissue. Here's a solid point going through a block of gelatin:
Notice that they don't have to clamp the gelatin to the table. It just sits there and the bullet goes through. It doesn't go flying off the table because a bullet hit it.
Here it is with soft point ammo:
That's the purpose of soft point ammo. It expands on impact and transfers much more kinetic energy to the target. STILL - even with soft point ammo - a small block of gelatin doesn't show much lateral displacement from being hit with it, but you think that JFK's entire body is going to be deflected (over the course of a half second) from his head being hit. You make this point solely by assertion and not by reference to any physical principle or experiment whatsoever. His body should do that simply because you say his body should do that.
I don't ignore the backward movement. In fact, I take into account the entire sequence, and both movements. You seem to believe that having your brain blown out is not going to have any muscular effects over a full half second (9 frames at 18 frames/s). That's nonsense. The entire nervous system is going "where did the brain go" in less than a tenth of a second. Furthermore, as I pointed out, if your head is leaning forward, and you get wacked on the back of the head, your head is going to bob forward and then rebound. I account for both motions, you simply want to ignore the forward motion because it conflicts with your conclusion. I'd be willing to also bet that the actual forward motion at the time of impact has never been pointed out to you before.
So, here we go... kinetic energy (KE) is 1/2 mv^2, so we are talking about a total kinetic energy of roughly 1840 Joules, that's less than a baseball fast pitch, as discussed here:
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http://wredlich.com/ny/2013/01/projectiles-muzzle-energy-stopping-power/
Projectiles, Kinetic/Muzzle Energy and Stopping Power
Posted by warren on 23 January 2013, 6:13 pm
When bad guys are shot in Hollywood movies, they fly backward from the force of the shot and are immediately disabled.
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Now, remember, a baseball fast pitch of around 2000 Joules kinetic energy is going to transfer most of that energy to your body if it hits you straight on, because it is a big round ball that doesn't penetrate, pass through, and retain significant KE to keep going. If you get hit by a baseball, does it knock you off your feet when you are standing up? No. This happens in baseball pretty regularly, and batters don't go flying back into the catcher and the umpire.
So, to recap:
1. You don't seem to know how deer, gelatin, or anything else normally reacts to getting shot, but you believe that JFK's body should react differently from all of those other things.
2. You believe that the effect of a bullet impact on a head is delayed until after the bullet has passed through the head, manifests itself over the course of a half second later, and that what the head actually does at impact is not important.
3. You believe these things based on no apparent understanding of physics or ballistic experience or experimentation.
4. You have no explanation for the forward motion of JFK's head at the point of impact. Instead, you seem upset that I pointed it out to you for the first time.
Yes, I get it. You don't think JFK's body should have done what it did based on your personal incredulity. You want to do this by looking at something that occurs over the course of a half second well after actual impact of the shot. You also don't want to propose an actual trajectory or shooter position of this supposed shot from the front.
The more entertaining "front shot" folks have realized there isn't a trajectory that "pushes the head up" unless the shot is fired from inside the car, so they have moved on to proposing that one of the Secret Service agents inside the car fired the shot. Apparently, neither of the Connallys nor Jackie managed to notice a gun going off inches from them.
You appear to believe that a projectile traveling at least 2000 feet per second before hitting the bone of a human scull will propel the head and body of that person a very minor amount in the same direction in which it is traveling before propelling the head and body a very significant amount in the opposite direction in which it was traveling.
You got the first half right. Shooting someone in the head with full metal jacket ammo does not propel either their head or their body very far in any direction. Doesn't do it to a deer, and it doesn't do it to a pig head that isn't even attached to anything:
Watch the slo-mo of the bullet going through the pig's head at around 1:35. What does it do? Oh noes!! It deflects slightly in the direction the bullet passed, and then rolls back toward the direction of the shot. It doesn't even get knocked off the table.
You simply believe, based on nothing, that being shot in the head from the front will throw your body backwards, despite the fact that nothing else behaves that way when shot.
Here are some more shots to simulated heads:
NONE of them do what you say they should do when shot. Not a one.
Can you point to ANYTHING - any relevant physical calculation or experiment - which supports your claim that a shot to the head from the front will result in an immediate forward motion of the head followed by a slow roll backwards of the entire body, other than your simply saying it should do that?
And let's not forget the other thing in the Zapruder film you are completely ignoring. Why is the blood and tissue ejected from the head primarily upward and forward, with no significant blood spatter going rearward? Perhaps, as above, it is personally obvious to you for some reason that being shot from the front sends blood splatter forward into the direction from which the shot came, but you should let forensics investigators in on your fascinating discovery.