The physics of "back and to the left"

[Michael T. Griffith]

Here's a nice little demonstration of why a bullet from the grassy knoll could not have flung JFK back into his seat. A bullet has just way too little mass to move an adults head so violently back and to the left. A bullet only has enough mass to move an adult head a little bit - which is why Oswalds bullet to JFKs head was only able to move JFKs head forward about 2 inches as seen in the Zapruder film when it is slowed down.

https://www.youtube.com/shorts/WvqTnqR2kn0

Itek did a study on this and determined the same thing: that no bullet could have caused JFK's violent backward motion. Dr. Mantik reviewed Itek's study, did his own calculations, and his calculations are very close to Itek's. The fact that no bullet could have caused the backward motion was one of the things that led Dr. Mantik to consider the idea of film alteration.

The problem for lone-gunman theorists is that they have no innocent plausible explanation for the backward movement. The jet-effect theory and the neuromuscular-reaction theory are just about equal in absurdity and implausibility.

https://www.kennedysandking.com/john-f-kennedy-reviews/nova-s-cold-case-jfk-junk-science-pbs

https://www.jfkassassinationforum.com/index.php/topic,2623.msg92145.html#msg92145

https://www.jfkassassinationforum.com/index.php/topic,2623.msg92315.html#msg92315

https://www.jfkassassinationforum.com/index.php/topic,2623.msg92343.html#msg92343

https://www.themantikview.org/pdf/Omissions_and_Miscalculations_of_Nicholas_Nalli.pdf
https://www.kennedysandking.com/john-f-kennedy-articles/the-omissions-and-miscalculations-of-nicholas-nalli

[Michael Carney]

Not implausible or absurd if it was a frangible round coming from JFK’s left rear.

[Matt Grantham]

 Camera motion and braking are also possibilities for the temporary forward motion at 313

  I have not checked out the entire thread, but I assume there are no filmed reenactments or reasonable facsimiles  Wouldn't that serve as  confirmation for iteks models

 Is there a link showing Mantik's evaluation of Itek's study?

[Jerry Organ]

Camera motion and braking are also possibilities for the temporary forward motion at 313

A bullet strike from behind causes Kennedy's head to violently move forward. Connally and Kellerman movements are a continuation of movement started earlier. If a panning motion, all would move forward equally. Mrs. Connally and Greer hardly move, so braking not an issue either.

[Matt Grantham]

Lets take it back a few more frames  There was a researcher that examined all this much more closely and there was forward motion of most of  those in the limo Kelleraman and the Conally's are moving slightly forward even in your clip[ but the general trend needs to be viewed in a longer clip

[Andrew Mason]

The jet-effect theory and the neuromuscular-reaction theory are just about equal in absurdity and implausibility.

The jet-effect is basic physics.  It has been duplicated in real life by, among others, Chad Zimmerman with his turkey shoot:

[Tim Nickerson]

The jet-effect theory and the neuromuscular-reaction theory are just about equal in absurdity and implausibility.

"The motion of the President's head as shown in the Zapruder film does not indicate the direction of the shot in my opinion, but the visible blow-out of tissue and bony fragments in frame 313 and subsequent frames do conclusively indicate the bullet came from behind. The head motion subsequently is interpreted as due to involuntary muscle extension and not due to the direction of the injury."

--Dr. Fred Hodges, Chief of Neuroradiology at Johns Hopkins Hospital, President of the Society of American Neuroradiology, and later Professor of Radiology at Mallinckrodt Institute of Radiology at Washington University in St. Louis, Mo.

Neuroradiology is the clinical sub-specialty concerned with the diagnostic radiology of diseases of the central nervous system, brain, head and neck, through the use of x-ray, MRI, CT and angiography.

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"Immediately after the shot through the head the President took rather abruptly an almost erect position before slumping over to the left. This straightening is to be considered a sudden opisthotonic reflex movement due to decerebration."

-- Richard Lindenberg, M.D,  Director of Neuropathology for the State of Maryland, Clinical Professor in Forensic Pathology and Lecturer in Neuroanatomy at University of Maryland

Neuropathology is the study of diseases of the brain, spinal cord, and nerves.

[Matt Grantham]

The jet-effect is basic physics.  It has been duplicated in real life by, among others, Chad Zimmerman with his turkey shoot:

 The more resistance on impact, such as occipital bone, the greater the force transfered to the head Alvarez completely ignores this force by using a melon