A Bullet's (lack of) Transfer Of Kinetic Energy

[W. Niederhut]

4 hours ago, Pat Speer said:

His head slams down and slightly forward. It then snaps back and to the left. 

 

Pat,

I don't see the head "slamming down" on this Zapruder clip.  I see it slamming backward.

JFK's head was, obviously, tilted down and forward before the fatal head shot, as he clutched his throat, then it was abruptly hit and slammed violently backward by the impact of the fatal bullet.  Jackie instinctively tried to retrieve brain matter that was blasted backward, behind the limo.

In contrast, a test/forensic bullet fired at a cadaver from the TSBD blew off the right half of the face.

 

[Pat Speer]

I can't get the gif to stay in my post, but here is a tracing showing the movement of Kennedy's head between Z312 and Z313. The back of the head jerks forward in comparison to the shoulder. I believe it was Tink who first noticed this back in 1967. I was there in 2013 for that matter when he realized the implications and said he was wrong and that the head didn't move forward, and that he was fooled by motion blur. But that's nonsense. The angle of the back of the head jerks forward from one o'clock to two o'clock. 

 

 

 

Edited February 25 by Pat Speer

[Chris Bristow]

It looks like JFK has his head leaning forward 35 degrees at fr312 and 50 degrees at fr313. I have to rotate my head 40 degrees more before my chin starts to bottom out on my chest. My head has to be horizontal for the chin to hit the chest. Maybe his chin could hit between 313 and 314, but I don't see any photographic evidence that his chin bounced off his chest or that his head reached anywhere near the end of its forward range.
  I also have doubts about characterizing his forward head movement as violent.  Jackie and J.C. both make similar head moments earlier. From 293 to 294 Jackie moves her head forward approx 3 inches. It should be farther than it looks or measures since she is moving toward the camera as well as to her left.
 I would think the 313 head movement is from a rear shot but does indicate a great force that would cause the head to bounce backward.

[Pat Speer]

This is gruesome as heck but when you focus on the back of his head and his right shoulder it is 100% clear that his head snaps forward and then springs back at a much slower velocity. 

 

Edited April 29 by Pat Speer

[Matthew Koch]

6 hours ago, Pat Speer said:

This is gruesome as heck but when you focus on the back of his head and his right shoulder it is 100% clear that his head snaps forward and then springs back at a much slower velocity. 

The forward motion is from the breaking of the car.

People have measured other peoples heads in the car and they move forward like JFK's  

[W. Niederhut]

7 hours ago, Pat Speer said:

This is gruesome as heck but when you focus on the back of his head and his right shoulder it is 100% clear that his head snaps forward and then springs back at a much slower velocity. 

On closer examination, it looks like this Zapruder film clip has been photo-shopped, with a "painting" of instantaneously appearing bloody matter in the right frontal area, and a deletion of the occipital skull and brain matter that was blasted backward behind the limo.

Why would Jackie have climbed on the back of the limo-- behind the back seat-- if this altered photo representation were accurate?

Edited November 29, 2022 by W. Niederhut

[Sandy Larsen]

On 11/27/2022 at 11:00 PM, Chris Bristow said:

I think the kickback just takes longer to spend the initial energy from the gas expanding. It has to move backwards a couple inches and push into the arm to spend its energy. The bullet on the hand has long left the barrel.

 

Oh, of course! I shouldn't have taken those comments I read so seriously... these people aren't all physicists after all.

Okay...

(Those not interested in the math should drop down to my conclusions.)

Upon leaving the barrel, the bullet has (1/2)mv^2 of kinetic energy and the gun has an EQUAL amount of kinetic energy in the opposite direction. For the bullet it is

Eb = 1/2 Mb Vb^2

and for the gun it is

Eg = 1/2 Mg Vg^2

where E is kinetic energy, M is mass, V is velocity, and ^2 means mathematically squared. Subscript b is for bullet and subscript g is for gun.

From these equations we can see that the reason the kinetic energies of the gun and bullet can be the same, despite their vast difference in speed, is that that the gun is much heavier than the bullet.

As I said, the energies in the bullet and gun are equal upon the bullet's exit, so we let the two equations equal each other

1/2 Mg Vg^2 = 1/2 Mb Vb^2

Using algebra to solve for the velocity of the gun, we get

Vg^2 = (Mb/Mg) Vb^2

sqroot( Vg^2 ) = sqroot( (Mb/Mg) Vb^2 )

Vg = sqroot( Mb/Mg ) Vb

where sqroot means the mathematical square root.

Following are the characteristics of the Carcano rifle and bullet, as far as I could find. (Not that I believe that gun was used... In fact, I don't.):

Mass of the gun:      3860 g     (8.5 lb)
Mass of the bullet:  10.5 g
Bullet velocity:         2300 fps
Barrel Length:           3.33 ft      (40 in)

If the gun is held far enough away from the shoulder that the bullet exits the barrel before the butt hits the shoulder, the velocity of the gun before it hits the shoulder will be

Vg = sqroot( Mb/Mg ) Vb

Vg = sqroot( 10.5/3860 ) 2300 fps

Vg = 120 fps

Wow, that's faster than I expected. If someone shoots the rifle without holding onto it, it will go flying back at 120 feet per second!

Let's see how far the gun needs to be held from the shoulder so that it doesn't hit the shoulder till right after the bullet exits the barrel. Because that is the point in time where our calculated velocities are made.

When the gun is fired, the bullet begins with a zero velocity and then is flying at 2300 fps when it exits the barrel. We would need to know how quickly the barrel's gas pressure increases in order to determine the acceleration of the bullet as it travels through the barrel. Instead, lets just assume that the speed of the bullet increases linearly. This will give us an approximate answer to our question.

The average velocity of the bullet from one end of the barrel to the other is (0+2300)/2 = 1150 fps. Dividing the length of the barrel, 3.33 ft, by that velocity gives us the appropriate time for the bullet to exit, which is 0.003 seconds.

Now, the question is, how far will the gun move toward the shoulder in that period of time. We multiply the speed of the gun, 120 fps, by that time and we get approximately 0.36 feet, or 4.3 inches.

 

Conclusions

It takes about 0.003 seconds after firing for the bullet to exit the barrel of a 40" Carcano rifle.

If you fire an 8.5 lb, 40" Carcano rifle with the butt 4.3" away from your shoulder, the gun will fly toward your shoulder and hit it at a velocity of 120 fps about 0.003 seconds later.

At that point, the gun and bullet will each have received the same amount of energy from the blast, but the gun will continue receiving energy till the pressure of the hot gas drops to ambient level.

It would be useful to know roughly how much more energy the gun receives from the blast after the bullet exits the barrel.

 

[Pat Speer]

2 hours ago, Matthew Koch said:

The forward motion is from the breaking of the car.

People have measured other peoples heads in the car and they move forward like JFK's  

Nope. The braking was not sudden enough to cause a sudden lunge forward. (Let's not forget that many CTs suspect Greer's involvement because he slowed to a near stop--thus making JFK an easier target--and only took off after the fatal shot was fired...A sudden slam down on the brakes before a jump forward would have, on the other hand, made JFK a more difficult target.) It should also be pointed out, I believe, that the  driver-did-it excuse for Kennedy's movements was a myth originally pushed by the likes of Baden to explain why Kennedy went backwards after he first jolted forward. (He was just sitting there, y' see, and the driver floored it and caused him to fall back in the seat.) It simply isn't true. 

As far as your other point, compare JFK's head to Jackie's. What you might be thinking of is that Tink Thompson (under the influence of David Wimp) came to believe the forward motion of the head was an illusion, caused by the blur in image 313. But that's just desperate, IMO. Compare the back of JFK's head against his shoulder. It's absolutely clear his head goes forward. 

Edited November 29, 2022 by Pat Speer

[Pat Speer]

1 hour ago, W. Niederhut said:

On closer examination, it looks like this Zapruder film clip has been photo-shopped, with a "painting" of instantaneously appearing bloody matter in the right frontal area, and a deletion of the occipital skull and brain matter that was blasted backward behind the limo.

Why would Jackie have climbed on the back of the limo-- behind the back seat-- if this altered photo representation were accurate?

Oh my. The word is that a chunk of JFK's brain landed on the back of the car and she crawled out to get it. The car was moving. His head exploded. Stuff flew up in the air. Some of the slower moving stuff went up and fell down in rapid succession. Some of the brain matter landed in front of Kennedy. Both Connallys said they were soaked. This one large piece landed on the back of the car. 

Edited November 29, 2022 by Pat Speer

[Matthew Koch]

34 minutes ago, Pat Speer said:

Nope. The braking was not sudden enough to cause a sudden lunge forward. (Let's not forget that many CTs suspect Greer's involvement because he slowed to a near stop--thus making JFK an easier target--and only took off after the fatal shot was fired...A sudden slam down on the brakes before a jump forward would have, on the other hand, made JFK a more difficult target.) It should also be pointed out, I believe, that the  driver-did-it excuse for Kennedy's movements was a myth originally pushed by the likes of Baden to explain why Kennedy went backwards after he first jolted forward. (He was just sitting there, y' see, and the driver floored it and caused him to fall back in the seat.) It simply isn't true. 

As far as your other point, compare JFK's head to Jackie's. What you might be thinking of is that Tink Thompson (under the influence of David Wimp) came to believe the forward motion of the head was an illusion, caused by the blur in image 313. But that's just desperate, IMO. Compare the back of JFK's head against his shoulder. It's absolutely clear his head goes forward. 

David Lifton already coved the head moving down in Best Evidence maybe go back and re read about that.

Instead of citing the measurements being wrong we get this piece of Cognitive Disadance from Pat Speer: Let's not forget that many CTs suspect Greer's involvement because he slowed to a near stop--thus making JFK an easier target--and only took off after the fatal shot was fired...A sudden slam down on the brakes before a jump forward would have, on the other hand, made JFK a more difficult target.)It should also be pointed out, I believe, that the  driver-did-it excuse for Kennedy's movements was a myth originally pushed by the likes of Baden to explain why Kennedy went backwards after he first jolted forward. (He was just sitting there, y' see, and the driver floored it and caused him to fall back in the seat.) It simply isn't true. Like what does that have to do with anything But that's just desperate, IMO? 

The heads Connally and Kennedy when measured moved the same. You are grasping at straws with David Wimp, I'm citing Donald Thomas about that. I was at the 50th Lancer Presentation when they showed that they are the same. 

Edited November 29, 2022 by Matthew Koch

[Tom Gram]

24 minutes ago, Pat Speer said:

Nope. The braking was not sudden enough to cause a sudden lunge forward. (Let's not forget that many CTs suspect Greer's involvement because he slowed to a near stop--thus making JFK an easier target--and only took off after the fatal shot was fired...A sudden slam down on the brakes before a jump forward would have, on the other hand, made JFK a more difficult target.) It should also be pointed out, I believe, that the  driver-did-it excuse for Kennedy's movements was a myth originally pushed by the likes of Baden to explain why Kennedy went backwards after he first jolted forward. (He was just sitting there, y' see, and the driver floored it and caused him to fall back in the seat.) It simply isn't true. 

As far as your other point, compare JFK's head to Jackie's. What you might be thinking of is that Tink Thompson (under the influence of David Wimp) came to believe the forward motion of the head was an illusion, caused by the blur in image 313. But that's just desperate, IMO. Compare the back of JFK's head against his shoulder. It's absolutely clear his head goes forward. 

I’m not sure how legit this is, since I agree that the film appears to show JFK’s head jolting forward and Jackie remaining stationary, but ITEK in the 70s calculated basically the exact same overall magnitude of forward movement for Jackie as JFK between Z312 and Z313 - just most of the momentum of JFK was in his head and Jackie’s was in her shoulders, etc. Their “explanation” was that the shock from the headshot was transmitted through Jackie’s hand on JFK’s chest, or something like that. Jackie’s forward movement in the film just looks like blur to me, but ITEK claimed to have corrected for that sort of thing. If Jackie really did move as much as ITEK said she did, and it’s a really frigging big if, a coincidentally timed tap of the brakes seems to make a lot more sense than a transmitted shockwave launching her forward a few inches. 

[W. Niederhut]

37 minutes ago, Pat Speer said:

Oh my. The word is that a chunk of JFK's brain landed on the back of the car and she crawled out to get it. The car was moving. His head exploded. Stuff flew up in the air. Some of the slower moving stuff went up and fell down in rapid succession. Some of the brain matter landed in front of Kennedy. Both Connallys said they were soaked. This one large piece landed on the back of the car. 

The gelatinous, blob-like CIA photo-shopping on this clip reminds me of the special effects in the movie, The Blob.

It is also completely inconsistent, physiologically, with the photo of JFK's cadaver showing a small bullet hole/entry wound in the right frontal temple.

Edited November 29, 2022 by W. Niederhut

[Bill Brown]

From an article by Nick Nalli:

"The Ghost of the Grassy Knoll Gunman"

 

https://jfkfiles.blogspot.com/2021/06/the-ghost-of-grassy-knoll-gunman.html?fbclid=IwAR1gfLbKdWjAO51uacjALtKShc6H0ygWgGOZpfTJ7hd8p9FcgKnklJekoVE

[Sandy Larsen]

On 11/27/2022 at 11:00 PM, Chris Bristow said:

I don't think I should speculate any further cuz it feels like I could be completely wrong in the end.

 

It takes experience in solving physics problems in order to look at them in the right or best way to solve them.

Here's an example. When a person looks at a a balloon that has been blown up and let loose to fly through the air, he typically thinks the the air exiting the neck "hits" the air around it and thereby pushes the balloon around. If that were the case, rockets could not fly in outer space as there would be no air for its exhaust gas to blow against.

Here's the correct way to think of that balloon. For this analysis, let's ignore atmospheric pressure. Before the balloon is let go, there is air pressure pressing on its inside surface. Since the force is applied to every side of the surface, there is no net force. (i.e. for every point of force pointing in one direction, there is an equal and opposite force on the opposite side that cancels it out.) So the air pressure doesn't move the balloon.

Then the guy lets go and the neck of the balloon opens up.

Now, here's the important part. The small circular area of the neck that is opened up no longer has pressure applied to it... the force there is gone. And yet an equal amount of force remains on the opposite side of the balloon. And so the balloon moves in that direction.

And so, we see that the force pushing the balloon is really on the inside of the balloon.

 

[Paul Cummings]

2 hours ago, Sandy Larsen said:

 

Oh, of course! I shouldn't have taken those comments I read so seriously... these people aren't all physicists after all.

Okay...

(Those not interested in the math should drop down to my conclusions.)

Upon leaving the barrel, the bullet has (1/2)mv^2 of kinetic energy and the gun has an EQUAL amount of kinetic energy in the opposite direction. For the bullet it is

Eb = 1/2 Mb Vb^2

and for the gun it is

Eg = 1/2 Mg Vg^2

where E is kinetic energy, M is mass, V is velocity, and ^2 means mathematically squared. Subscript b is for bullet and subscript g is for gun.

From these equations we can see that the reason the kinetic energies of the gun and bullet can be the same, despite their vast difference in speed, is that that the gun is much heavier than the bullet.

As I said, the energies in the bullet and gun are equal upon the bullet's exit, so we let the two equations equal each other

1/2 Mg Vg^2 = 1/2 Mb Vb^2

Using algebra to solve for the velocity of the gun, we get

Vg^2 = (Mb/Mg) Vb^2

sqroot( Vg^2 ) = sqroot( (Mb/Mg) Vb^2 )

Vg = sqroot( Mb/Mg ) Vb

where sqroot means the mathematical square root.

Following are the characteristics of the Carcano rifle and bullet, as far as I could find. (Not that I believe that gun was used... In fact, I don't.):

Mass of the gun:      3860 g     (8.5 lb)
Mass of the bullet:  10.5 g
Bullet velocity:         2300 fps
Barrel Length:           3.33 ft      (40 in)

If the gun is held far enough away from the shoulder that the bullet exits the barrel before the butt hits the shoulder, the velocity of the gun before it hits the shoulder will be

Vg = sqroot( Mb/Mg ) Vb

Vg = sqroot( 10.5/3860 ) 2300 fps

Vg = 120 fps

Wow, that's faster than I expected. If someone shoots the rifle without holding onto it, it will go flying back at 120 feet per second!

Let's see how far the gun needs to be held from the shoulder so that it doesn't hit the shoulder till right after the bullet exits the barrel. Because that is the point in time where our calculated velocities are made.

When the gun is fired, the bullet begins with a zero velocity and then is flying at 2300 fps when it exits the barrel. We would need to know how quickly the barrel's gas pressure increases in order to determine the acceleration of the bullet as it travels through the barrel. Instead, lets just assume that the speed of the bullet increases linearly. This will give us an approximate answer to our question.

The average velocity of the bullet from one end of the barrel to the other is (0+2300)/2 = 1150 fps. Dividing the length of the barrel, 3.33 ft, by that velocity gives us the appropriate time for the bullet to exit, which is 0.003 seconds.

Now, the question is, how far will the gun move toward the shoulder in that period of time. We multiply the speed of the gun, 120 fps, by that time and we get approximately 0.36 feet, or 4.3 inches.

 

Conclusions

It takes about 0.003 seconds after firing for the bullet to exit the barrel of a 40" Carcano rifle.

If you fire an 8.5 lb, 40" Carcano rifle with the butt 4.3" away from your shoulder, the gun will fly toward your shoulder and hit it at a velocity of 120 fps about 0.003 seconds later.

At that point, the gun and bullet will each have received the same amount of energy from the blast, but the gun will continue receiving energy till the pressure of the hot gas drops to ambient level.

It would be useful to know roughly how much more energy the gun receives from the blast after the bullet exits the barrel.

 

https://www.youtube.com/watch?v=mKAnk2XVnDE