You have to take into account gravity and recoil from the head explosion. It is complicated because JFK was leaning forward when hit so the impulse from the head explosion has to push his body up initially against gravity and then gravity takes over and he falls.
There is no evidence that a person shot in the head generates muscle spasms. There are many films of people being shot in the back of the head. They just collapse and fall.
However, there is evidence of matter exploding out of the right front of JFK's head likely carrying momentum much greater than the forward momentum of the bullet. The recoil from this would be an equal and opposite impulse to the head pushing it back and to the left.
one cannot ignore the explosion of the head. The momentum of the matter exploding in a generally forward direction from the front right side of his head can be, and likely is, much more than the forward momentum imparted by the bullet.
Let’s take one point at a time.
You have to take into account gravity …
JFK was sitting pretty much upright, with a slight lean forward. During the early part of the movement, z313-z316, the movement was even slightly “uphill”. But it never mattered. The acceleration was constant. Even when he did start to tilt backwards, the acceleration he would get from gravity was a fraction of the acceleration
Using physics graduate student Michael Hoffman’s calculations, the acceleration of the head during z314-z315. z315-z316 and z316-z317 was 0.26 G’s, 0.26 G’s and 0.17 G’s. Note, I converted Hoffman’s numbers from feet per second squared to G’s. If the head and body were reclined 90 degrees, lying flat on his back, and JFK was free to continue to fall, gravity could accelerate JFK’s head at 1.0 G’s.
My understanding of classical physics is pretty rudimentary. But acceleration of a simple inverted pendulum, shown at:
http://pmaweb.caltech.edu/~phy003/handout_source/Inverted_Pendulum/InvertedPendulum.pdfThe acceleration would be 1 G times the sin of the angle, 1 G * sin (a) where the angle is 0 degrees if JFK is sitting bolt upright, 45 degrees if he is greatly reclined backwards and 90 degrees if he is lying on his back.
Yes, I know, this is not a simple inverted pendulum, because JFK’s torso did not contain negligible mass. Still, I think this what I would expect, an acceleration proportional to the sin of the angle.
Acceleration due to gravity alone would not reach 0.26 Gs until JFK was reclined back at 15 degrees. The sign of 15 degrees is roughly 0.26. Looking even at z317, which is getting pretty late in the acceleration, he still seems to be sitting mostly upright. He may be leaning a significant amount to his left. It’s hard to tell. But this would not affect his acceleration backwards.
It is clear to me that the acceleration of JFK’s head backwards from z313 through z317 was not caused by gravity. Nor was it caused by the acceleration of the car, which was slightly accelerating, but only providing less than a tenth of the acceleration needed to account for JFK’s motion.
No, the acceleration was caused by something else. If not by a neurological spasm than there is simply no other explanation for this constant acceleration. Unless one goes with a stream of bullet scenario, where with each Zapruder frame, another bullet struck from the front adding more momentum to JFK’s body moving backwards.
You have to take into … and recoil from the head explosion
The recoil from the head explosion. By which, I believe, you mean the ‘Jet Effect’. But like the ‘bullet from the front’ scenario, this would give a one-time impulse pushing the head backwards. This should not result in a constant acceleration of the head backwards, unless material was spewing out of JFK’s head, carrying a good deal of momentum forward, for over a quarter of a second.
There is no evidence that a person shot in the head generates muscle spasms. There are many films of people being shot in the back of the head. They just collapse and fall.
And these are all people shot in the head with a rifle bullet? And in all cases, the bullet went through near the center of the brain? Was this established in all cases with an autopsy?
In a sense, this cannot be demonstrated. One cannot run an experiment by shooting a person in the head with a rifle bullet. If one does, by accident, have such a video, it cannot be shown because it is an affront to human dignity. I understand that a reporter was murdered by a soldier with a shot through the brain using an assault rifle and it seems to show a neurological spasm, but this cannot be shown, and I have never seen it, because it would be an affront to the dignity of his family. Showing video of JFK’s murder seems to be the only exception.
For those who argue against the Neurological spasm, they need the following guidelines to be strictly adhered to.
1. Only video of people is to be used as evidence.
2. Video of animals being shot through the brain are to be ignored, because, for all we know, for unknown reasons, all animals would react one way but people would react another. Even demonstrating this for a dozen different species, some of them primates, would make no difference.
3. Without any proof from a video of a human being shot, the default assumption is that the Neurological Spasm does not occur in humans, until it is proven that it does. These guidelines put LNers, like myself in an impossible Catch-22 position. We can’t run an experiment but if such a video falls into our laps, we can’t use it because it would be an affront to human dignity. And we would likely be sued by the victim’s family.
Let me propose a different set of guidelines:
1. Only video of people is to be used as evidence.
2. Video of animals being shot through the brain are to be ignored, because, for all we know, for unknown reasons, all animals would react one way but people would react another. Even demonstrating this for a dozen different species, some of them primates, would make no difference.
3. Without any proof from a video of a human being shot, the default assumption is that the Neurological Spasm does occur in humans, until it is proven that it does not. I am using the same guidelines as before except I have reversed Guideline 3. If this is done, now CTers are in a Catch-22. Even if the Neurological Spasm were a myth, for both animals and humans, they could not prove this. All experiments on animals are considered irrelevant. All video of humans being shot in the head with a rifle bullet, causing their brains to explode out of their head, but no Neurological Spasm being observed, could not be used to disprove the Theory of Neurological Spasm, because the showing of such video would be an affront to human dignity, and might get them sued by the victim’s family.
Instead, let me propose a more reasonable set of guidelines.
1. If we have good videos, of people being shot, with rifle bullets, causing their brains to explode out of their heads, the results from these videos and these videos only should determine if the Neurological Spasm occurs in humans or not. Video of animals being shot would be considered irrelevant.
2. If we cannot use Guideline 1, because of human dignity considerations, fear of lawsuits, or for other reasons, then we must rely of video of animals being shot in the head.
If the Neurological Spasm is seen in animals, then it must be considered to be good evidence that it would also occur in humans. No, it’s not absolute proof. We don’t get absolute proof in this world for anything. But it should be considered good evidence
Under this last set of guidelines, which is fair to both sides, and does not put either side into an impossible Catch-22 situation, it is clear that Neurological Spasm in humans is quite possible. And, since this is the only possible explanation for the acceleration of JFK’s backwards, it must be considered the most probable explanation as to why JFK’s head moved and accelerated backwards continuously during z313-z318.
