Back and to the right?

[Royell Storing]

  There's relatively little space between the backseat JFK was sitting atop and the Jump Seats in front of him. With the Limo accelerating through turns, it would be easy for a dead man tumbling onto the floorboard to get his feet/legs tangled underneath the Jump Seats.

[Gerry Down]

No. If the limousine is moving at a steady speed, it acts as an ‘inertial frame of reference’. Everything that happens inside will happen the exact same way as if the limousine is still.

Inside a moving vehicle, moving at a constant speed, you can toss a ball back and forth normally. The seats won’t seem to be pushing against you. Acceleration will affect you, but not velocity.

If you slow down or speed up, that’s a different story. But at a constant speed there is no effect. Afterall we are moving on a rotating Earth at hundreds of mph. And hurdling around the sun at thousands of miles an hour. But we don’t notice it. The velocity does not vary much from second to second.

The limousine did speed up slightly, but way too small an amount to account for the movement of JFK’s head.

However, my understanding of Physics is limited to only the most basic principles of Classical Newtonian Physics, which I learned in high school. We could use William Hoffman to evaluate if the wind could have been a significant force in pushing JFK’s head backwards.

Thanks, this is very helpful. It seems we can rule out what i was suggesting.

[Jerry Freeman]

 

Yes. The limousine was traveling at 8 mph.

Mr. SPECTER. How fast was the President's automobile proceeding at that time?
Governor CONNALLY. I would guess between 20 and 22 miles an hour, and it is a guess because I didn't look at the speedometer, but I would say in that range.

 

[Joe Elliott]

Quote from Joe Elliott:

Yes. The limousine was traveling at 8 mph.

Quote from Jerry Freeman, quoting Warren Commission testimony:

Mr. SPECTER. How fast was the President's automobile proceeding at that time?
Governor CONNALLY. I would guess between 20 and 22 miles an hour, and it is a guess because I didn't look at the speedometer, but I would say in that range.

A classic example of why one should not trust eyewitness memories, even of those who had not just been seriously wounded, and go with reliable evidence, like film.

20 to 22 miles an hour? If Clint Hill wasn’t a Cheetah, he was an Olympic Sprinter. As it was, he barely caught up to the limousine doing 16 mph, which was pretty good, considering he had to catch up and get up on the back of the limousine, while it was accelerating. If you needed someone to catch a cab, you could do worse than chose Clint Hill in his prime.

[Joe Elliott]

     Z304 - Z325 = Essentially 1 Second. Plus, the Limo is traveling DOWNHILL. COASTING DOWNHILL all by itself would increase the speed of an Extremely Heavy car like the JFK Limo. Get Real.

Oh yes, and you would know better than William Hoffman, a Physics graduate.

In what ways are you more qualified to make an accurate estimation of the velocity of the limousine than William Hoffman?

Why do you think an acceleration from 7.89 mph to 8.23 mph in about 1.2 seconds is unrealistic?

Can you list your qualifications?

[Joe Elliott]

I read where they had a hell of a time getting Kennedy out of the car; his feet were really jammed under the jump seat in front of him, apparently. Sounds like something related to a spasm of some sort. And someone said he had no shoes on when brought into the ER.

I don’t know human anatomy very well, but I think the muscles on the back on the calf are strongest. So I would think there would be a tendency for the legs to bend backwards, for the back to arch and legs to follow the same curve, with legs bending back.

Perhaps that could cause the feet to jam under a jump seat but I don’t know.

[Jerry Freeman]

Its 8mm Kodachrome II color film moved through the camera at an average speed of 18.3 frames per second, as determined by later tests.

https://www.jfk.org/the-collections/abraham-zapruder-film/abraham-zapruder-film-timeline/
The specs were rated 16 FPS so 18.3 is really pretty close.

[Joe Elliott]

https://www.jfk.org/the-collections/abraham-zapruder-film/abraham-zapruder-film-timeline/
The specs were rated 16 FPS so 18.3 is really pretty close.

The Zapruder camera did have a setting for 16 frames per second. It had no setting for 18.3 frames per second. But cameras varied from camera to camera, even of the same model. Alvarez studies of people clapping in the Zapruder film indicate that the filming rate had to be close to 16 frames per second, so it was set for 16 frames per second. However, the FBI tested Zapruder camera, not one of the same model but that very same camera, and found that at the 16 frames per second setting it actually filmed at 18.3 frames per second.

So, 18.3 frames per second is the better estimate for the film rate of the Zapruder film, not 16 frames per second.