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Author Topic: What physics reveals about the JFK event  (Read 1098 times)

Offline Andrew Mason

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Re: What physics reveals about the JFK event
« Reply #20 on: June 12, 2019, 01:39:12 AM »
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I suppose it has been calculated just how much jet-effect force would be required to cause Kennedy's movements backwards. Do you know if it has been shown that the explosive force reached a required standard?
The calculation is not difficult.  It all depends on how much mass is expelled from the head and what portion of the bullet energy it carries. 

The momentum is: p = square root of {2m(KE)} where m is the mass of the ejected matter and KE is the kinetic energy of that matter. 

Let's say the mass of ejected blood and brain matter was, conservatively, 100 g.  It was likely more.

The energy of that expelled mass can only make up a small fraction of the energy of the incoming bullet. This is because much of the bullet energy is used in deforming the bullet when penetrating the skull.  The energy of the deformed bullet plowing through the brain is converted into compression energy (pressure x volume of matter) of the brain material that is then converted to kinetic energy of the pressurized brain matter when the front of the skull ruptures. 

Conservatively, let's say only 10% of the bullet energy is converted into kinetic energy of the expelled brain matter.  A 10 g bullet moving at 1900 fps (580m/sec) carries kinetic energy (mv^2/2) of 1680 Joules.  This would mean that the 100 g. of ejected matter carried 168 J. of kinetic energy.  Using the formula for momentum, that means that the momentum imparted to the ejected matter was  p = sqrt{2 x .1 x 168) or about 6 kg m/sec of momentum.   This would propel the head (having a mass of, say, 13 lb or 6 kg)  back at a speed of about 1 m/sec.   

[Note: Another factor is gravity.  Once JFK's body was pushed far enough left, gravity would take effect.]

So even using these conservative estimates for the amount of matter ejected and its energy, there would be a significant momentum imparted to the head - enough to cause a visible rearward and leftward motion of the head.



Offline Jerry Organ

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Re: What physics reveals about the JFK event
« Reply #21 on: June 12, 2019, 03:50:09 AM »
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The calculation is not difficult.  It all depends on how much mass is expelled from the head and what portion of the bullet energy it carries. 

The momentum is: p = square root of {2m(KE)} where m is the mass of the ejected matter and KE is the kinetic energy of that matter. 

Let's say the mass of ejected blood and brain matter was, conservatively, 100 g.  It was likely more.

The energy of that expelled mass can only make up a small fraction of the energy of the incoming bullet. This is because much of the bullet energy is used in deforming the bullet when penetrating the skull.  The energy of the deformed bullet plowing through the brain is converted into compression energy (pressure x volume of matter) of the brain material that is then converted to kinetic energy of the pressurized brain matter when the front of the skull ruptures. 

Conservatively, let's say only 10% of the bullet energy is converted into kinetic energy of the expelled brain matter.  A 10 g bullet moving at 1900 fps (580m/sec) carries kinetic energy (mv^2/2) of 1680 Joules.  This would mean that the 100 g. of ejected matter carried 168 J. of kinetic energy.  Using the formula for momentum, that means that the momentum imparted to the ejected matter was  p = sqrt{2 x .1 x 168) or about 6 kg m/sec of momentum.   This would propel the head (having a mass of, say, 13 lb or 6 kg)  back at a speed of about 1 m/sec.   

[Note: Another factor is gravity.  Once JFK's body was pushed far enough left, gravity would take effect.]

So even using these conservative estimates for the amount of matter ejected and its energy, there would be a significant momentum imparted to the head - enough to cause a visible rearward and leftward motion of the head.


Note: Detached skull fragments were drawn at a larger scale than the head.

I'm wondering if the bullet entered at the back of the skull and created a few linear fractures radiating from the impact point, that ran into the lower rear of the skull.

Some of the surface of the skull at the point of impact was pushed forward such that it jutted forward of the intact skull above (see lateral X-ray):



The bullet fragmented into multiple pieces at the entry point and may not have had enough energy to fracture the intact skull opposite the entry. Possibly it was the bullet pressure wave that caused the fragmentation of skull above the right ear, or the gaping wound.

Nalli writes:

    "It is noted that the massive “defect” was not the “exit wound”
     of the bullet (as is commonly misunderstood), but rather
     corresponded roughly to the area where the maximum
     explosive energy was deposited by the bullet during its passage "

    "Here the large wound inflicted on the President's head was not a
     bullet exit wound, but rather the region of maximum temporary
     cavitation associated with KE transfer. This KE deposit
     propagated radially outward in the form of an expanding pressure
     wave resulting in a rupture and explosion of the skull."
 
    "However, all this said, note well that because such explosions are
     not necessarily the bullet outshoots, the momentum directly carried
     forward by a given bullet during passage may not be the primary
     player in a recoil effect."

The HSCA drawing seems to imply the right-side gaping wound was caused by the path of a bullet, or more precisely, one of its fragments, that impacted the inside of the skull to fracture it.

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Re: What physics reveals about the JFK event
« Reply #21 on: June 12, 2019, 03:50:09 AM »

Offline Bill Chapman

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Re: What physics reveals about the JFK event
« Reply #22 on: June 12, 2019, 07:28:02 AM »
Jackie Kennedy: "Top, behind the forehead"

Offline Andrew Mason

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Re: What physics reveals about the JFK event
« Reply #23 on: June 12, 2019, 05:00:00 PM »
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Note: Detached skull fragments were drawn at a larger scale than the head.

I'm wondering if the bullet entered at the back of the skull and created a few linear fractures radiating from the impact point, that ran into the lower rear of the skull.

Some of the surface of the skull at the point of impact was pushed forward such that it jutted forward of the intact skull above (see lateral X-ray):



The bullet fragmented into multiple pieces at the entry point and may not have had enough energy to fracture the intact skull opposite the entry. Possibly it was the bullet pressure wave that caused the fragmentation of skull above the right ear, or the gaping wound.
It is hard to say exactly what happened but I expect that the copper jacket ruptured on impact and much of the lead in the front part of the bullet melted and became a lead spray.  The copper jacket and a bit of still solid lead at the base is probably what passed through the skull. 

As an aside, it would have been nice if the ballistics experts actually weighed the copper jacket part and lead part of the bullet fragments separately to determine how much copper was recovered from the fragments.  We could then determine with a bit better detail what likely happened.  It would also help determine whether the fragments were from only 1 or 2 bullets.  If the amount of copper recovered exceeded the amount of copper of a single bullet we would know that more than one bullet struck in the car.

Quote
Nalli writes:

    "It is noted that the massive “defect” was not the “exit wound”
     of the bullet (as is commonly misunderstood), but rather
     corresponded roughly to the area where the maximum
     explosive energy was deposited by the bullet during its passage "

    "Here the large wound inflicted on the President's head was not a
     bullet exit wound, but rather the region of maximum temporary
     cavitation associated with KE transfer. This KE deposit
     propagated radially outward in the form of an expanding pressure
     wave resulting in a rupture and explosion of the skull."
 
    "However, all this said, note well that because such explosions are
     not necessarily the bullet outshoots, the momentum directly carried
     forward by a given bullet during passage may not be the primary
     player in a recoil effect."

The HSCA drawing seems to imply the right-side gaping wound was caused by the path of a bullet, or more precisely, one of its fragments, that impacted the inside of the skull to fracture it.
The size of the exit wound and the ruptured skull was definitely caused by the explosive exit wound.  However, there had to have been a significant piece of the missile to compress the brain matter that exploded out of the front part of the skull. Whether the skull ruptured because of the pressure alone before the bullet struck the skull from the inside or whether it occurred with the exit of that fragment through the skull is probably not possible to determine.

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Re: What physics reveals about the JFK event
« Reply #23 on: June 12, 2019, 05:00:00 PM »

Offline Jerry Organ

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Re: What physics reveals about the JFK event
« Reply #24 on: June 13, 2019, 02:51:05 AM »
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The size of the exit wound and the ruptured skull was definitely caused by the explosive exit wound.  However, there had to have been a significant piece of the missile to compress the brain matter that exploded out of the front part of the skull. Whether the skull ruptured because of the pressure alone before the bullet struck the skull from the inside or whether it occurred with the exit of that fragment through the skull is probably not possible to determine.

    "The fact that the fractures in a skull are due to temporary cavity formation
     was demonstrated by a series of experiments with skulls. When skulls were
     empty, the bullets 'drilled' neat entrances and exits without any fractures.
     When the skulls were filled with gelatin to simulate the brain, massive
     secondary skull fractures were produced."
          -- Vincent J.M. DiMaio ( You are not allowed to view links. Register or Login )

How about this? 
  • Bullet enters skull at rear, disintegrates by time it gets through the bone
  • Bullet hole at rear of skull, with a few fractures radiating downwards
  • Fragment from the bullet strikes the inside of the upper-right skull,
    causing a regular-sized exit wound hole; not the large gaping wound
  • Maybe the exiting bullet fragment disintegrated further, with two
    pieces causing the strikes on the windshield and windshield frame
  • Or maybe a sizeable skull fragment did detach, along with the hinged
    Devil's Ear opening out; this would allow the unimpeded passage of
    other bullet fragments
  • Exit wound fragment (or following fragment) continues onward to
    impact windshield
  • Fractures extend from the exit opening ("secondary" fractures)
  • Temporary cavity formation now occurs within the now-weakened cranium
  • Cavity forces large skull fragments to detach along existing skull fractures
    and/or new ones caused by the cavity, resulting in the large gaping wound
The only thing I go against in what DiMaio states is that the bullet caused fractures at the in-shoot and out-shoot, while DiMaio says there would have been "neat" holes without fractures.

The pressure impulse from the temporary cavity occurs in the wake of the bullet. Ballistic-wise, the brain is consider a liquid. I'm a layman when it comes to the medical evidence.
« Last Edit: June 13, 2019, 02:13:37 PM by Jerry Organ »

Offline Andrew Mason

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Re: What physics reveals about the JFK event
« Reply #25 on: June 17, 2019, 05:12:46 AM »
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How about this? 
  • Bullet enters skull at rear, disintegrates by time it gets through the bone
What do you mean by disintegrate? The bullet will compress and the jacket will rupture and molten lead will spray out.
   
Quote
  • Bullet hole at rear of skull, with a few fractures radiating downwards
If a bullet will just make a bullet sized hole in glass, why would it radiate cracks on the entrance to a skull?


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Re: What physics reveals about the JFK event
« Reply #25 on: June 17, 2019, 05:12:46 AM »

Offline Matt Grantham

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Re: What physics reveals about the JFK event
« Reply #26 on: Today at 12:06:11 AM »
 Ah yes the single frame of forward motion somehow takes precedence over the end result of the motion Lots of drawing from the review board folks and we all know how different those descriptions are than Parkland and Bethesda

 Where are all the nutters who believe that force in physics causes and equal and opposite reaction and like to show sheep falling towards the direction of the shot. They would of course say the initial forward motion is indicative of a shot from the front Such consistency from you folks
« Last Edit: Today at 12:11:57 AM by Matt Grantham »

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Re: What physics reveals about the JFK event
« Reply #26 on: Today at 12:06:11 AM »

 

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