Which clearly means that if you believe the Warren Commission's findings, the magic pristine bullet found on the stretcher at Parkland Memorial Hospital in Dallas, then I have some swamp land to sell you. Your statement also shows that you have very little knowledge of physics, or trajectory, or shooting at all for that matter. The way the spray comes off of Kennedy's head clearly delineates a frontal shot. His head snapping back means that it was a reaction to a force being applied from the front somewhere! Its Newton's 3rd Law - For every action there is an equal and opposite reaction. And accounts of one of the surgeons (Dr. Charles A. Crenshaw) who operating on Kennedy in the Emergency Room at Parkland Hospital that day stated that there was no bullet hole in the back of the cranium. He should know!
No, it was all wrapped up in too neat of a package by the Warren Commission. I was only a kid of eight years old at the time of the assassination, but there has been a lot of evidence come to light in the last 10 years that leads to a conspiracy being the cause of death. The lone assassin thing is all smoke and mirrors, I believe Lee Harvey Oswald was the fall guy for something much larger. It was a Coup d'tat staged at the highest levels of government. There was too much covered up for too long. You would think that the surgeons performing the autopsy would've been the top ones in that field of medicine, but they used a couple of Naval surgeons who had little, if any experience performing an autopsy prior to Kennedy's (which would've been the most important for forensic findings) during his career. No, there are too many new questions created by the Warren Commission's findings. And I do agree that the first shot, where Kennedy clutches his throat came from the rear, but the kill shot came from the front!
You are right in your analysis but wrong in your conclusion.
The person only opined on the nature of the bullet coming from behind, and not on any other matter.
The truth is, the bullet clearly does come from behind and exits out of the front, leaving a pretty big hole in JFK's face.
But that doesn't mean the magic bullet found on the stretecher is legit, or anything else in the Warrens findings are legit. It is a reasonable conclusion to draw from watching the film.
Coming to that conclusion does not mean that one accepts all the conclusions of the Warren report, or the legitimacy of the pristine bullet, at all. I have no idea what makes you think it would.
That bullet was not "pristine." It looks pristine from one angle, and that's the image the conspiracy buffs use. The other side of the bullet looks like s**t.
The spray of blood and brain matter flies out toward the FRONT of the car. A huge flap of the President's skull flips out and forward as well. The head actually moves FORWARD for a frame or two, then snaps violently back. I'm afraid you're the one who does not undertand physics. Nobel Prize winning physicist Luis Alvarez explained the "jet effect" that caused the spray exiting forward to propel the head back.
Furthermore, I might add, Kennedy's back brace would have restrained his torso from bending forward, but the conspiracy kooks never discuss how these sort of things might effect what happend. That and of course how there is NO evidence of any other shooter.
"...I was finally convinced that the assassination buffs were right; there had to be a real explanation of the fact that the President’s head did not fall back, but was driven back by some real force.
And the answer turned out to be simpler than I had expected. I solved the problem (to my own satisfaction, and in a one-dimensional fashion) on the back of an envelope, as I sat in solitary splendor in the beautiful suite that the St. Louis hotel management supplied me in my capacity as president of the APS.
I concluded that the retrograde motion of the President’s head, in response to the rifle bullet shot, is consistent with the law of conservation of momentum, if one pays attention to the conservation of energy as well, and includes the momentum of all the material in the problem. The simplest way to see where I differ from most of the critics is to note that they treat the problem as though it involved only two interacting masses: the bullet and the head. My analysis involves three interacting masses, the bullet, the jet of brain matter observable in frame 313, and the remaining part of the head. It will turn out that the jet can carry forward more momentum than was brought in by the bullet, and the head recoils backward, as a rocket recoils when its jet fuel is ejected. (Col. William H. Hanson came to the same conclusion, independently.)
If a block of wood is suspended by strings from the ceiling, it is called a ballistic pendulum, and physicists or gunsmiths can calculate the velocity of a bullet shot into it to be
vB = vWMW/MB, (1)
where vW is the velocity of the wooden block after it stops the bullet, MW and MB are the masses of the wooden block and bullet. Equation (1) follows directly from the law of conservation of momentum:
vBMB = vWMW. (2)
In using a ballistic pendulum, we normally forget that the collision of the bullet and wooden block is very inelastic. Of the incoming kinetic energy of the bullet, only a small fraction appears as kinetic energy of the moving wooden block; the remaining fraction (1 – f) goes into heating the wood. If MB << MW,
KEW = f(KEB),
MWvW2/2 = f x MBvB2/2. (3)
From (3) and (2),
f = MB/MW (4)
For the case of a 10-g bullet, and a block weighing 10 kg, it can be seen that 99.9% of the incoming kinetic energy goes into heating the block, and only 0.1% appears as mechanical energy. Ballistic pendulums are designed so that they contain the inelastically dissipated energy. Unfortunately, the human head is not able to contain the major fraction of the energy carried in by the bullet. This tragic aspect of the assassination is clearly visible in frame 313 of the Zapruder film, and is discussed in detail in the reports of the autopsy surgeons.
The mechanism of the retrograde recoil turns out to be rather simple, if one remembers that 99.9% of the incoming energy must be accounted for. The momentum associated with a given amount of kinetic energy varies as the square root of the mass of the object carrying that kinetic energy:
p = (2MK)1/2 (5)
where p is the momentum, and K is the kinetic energy of the object with a mass M.
Figure 4 shows what happened when my friends and I fired bullets at melons that had been wrapped with Scotch glass filament tape, to mock up the tensile strength of the cranium. Under the influence of the bullet, some of the material making up the melon breaks through the reinforcement, and carries momentum in the forward direction. (Frame 313 of the Zapruder film shows this same phenomenon.) As we shall now see, the momentum carried forward in this way can be much larger than the momentum brought in by the bullet. For example, if the bullet weighed 0.1% of the melon weight, and if 10% of the incoming kinetic energy was used to propel 10% of the mass of the melon forward, then the momentum of the jet expelled forward would be (10)1/2 times that of the incoming bullet. (I will use subscripts, b for bullet, j for forward moving jet, and m for melon.)
Pj = (2MjKj)1/2 = (2 x 100Mb x 0.1Kb)1/2
= (10)1/2 (2MbKb)1/2 = (10)1/2pb (6)
since = Mj = 0.1Mm 100Mb, Kj = 0.1Kb. The melon would then recoil backward with about twice the velocity it would have been expected to go forward, assuming it were made of wood. This is because the melon, acting at first as a ballistic pendulum, acquires a forward velocity equal to vm|BP = pb / Mm. (The notation vm|BP means the velocity one would expect the melon to have if it contained all the kinetic energy of the bullet, as a ballistic pendulum does.) But in the center of mass of the system of the melon, which is moving “forward” with the expected velocity, a jet moves forward with momentum equal to (10)1/2pb---as we have just seen. It gives the melon an equal and opposite momentum, in the moving (CM) system; in that system, pm = -(10)1/2pb. If we neglect the 10% loss of the mass by the melon to the jet, the recoil velocity of the melon (in the CM system) is -(10)1/2 times the expected value. Since velocities add vectorially, the final velocity of the melon (in the laboratory system) is [1- (10)1/2]vm|BP. Since the square root of 10 is close to 3.16, the observed velocity of the melon is about –2vm|BP.
If one wants to know more about the details of the transfer mechanism of kinetic energy from the bullet to kinetic energy of the fragments thrown forward, he will have to ask someone more knowledgeable in the theory of fluid mechanics than I am. My intuitive feeling is that the conical shape of the interaction zone is the key to the nonnegligible efficiency of energy transfer. (It is clear that an appreciable mechanical energy transfer is only possible if the incoming energy can avoid “being thermalized.”) The conical region is defined by the small entrance hole and the much larger exit hole in the melon. Transmission lines with tapered internal conductors are efficient transformers of electrical energy, and a tapered bullwhip can smoothly transform the energy given to a large mass, by the flick of the wrist, into roughly the same energy of a much smaller mass at the tip of the whip. The “crack” of the whip occurs when the tip of the whip goes supersonic. I believe that in a somewhat analogous manner, but of course in the opposite direction, the kinetic energy of the bullet is given in a “tapered region” to a progressively larger mass in the melon, to achieve the modestly efficient energy transfer that is demonstrated in our experiments."