In all honesty, it's not the theory yet. Just an idea. But I think you're mistaken by thinking
'that JBR's body would have been the driving force in that scenario' . If someone would grap JBR by her shirt and shovel into the edge of the knob then
power of the force should be calculated with the following parameters:
- power of the force from attacker;
- mass of the subject (JBR weight);
- distance between the mass and knob;
- valatility of the knob (means, how stable the door is

....and resistance of the knob/door...
I'm not the math and physics major

. We need someone's help to make the proper equation here.....
OpenMind4U,
Many years ago, too many, I took physics at Uni. To get a handle on this you just use Newtonian Mechanics.
So assume JonBenet simply fell to the floor, the equation for the force hitting her head is
F = MG.
Where F is measured in Newtons, M is JonBenet's weight in Kilograms, and G is the force of Gravity, e.g a constant number.
Another way to think about it is consider experimenting with JonBenet, bad I know!
And the experiment is to repeatedly lift JonBenet higher in the air then drop her to the ground.
The higher the height the more energy applied on impact, which is really the above equation plus the
potential energy stored in the height variable.
We do not need to do the physical experiments, simply apply the equations, using the first equation, e.g. fall to the floor as a baseline figure.
The more difficult, but not impossible, calculation is to then consider someone holding JonBenet by the neck and slamming her against a door knob.
Instead of Gravity doing the acceleration, its the person doing the holding, and the equation for this is:
F = MA
Where F is measured in Newtons, M is JonBenet's weight in Kilograms, and A is the metre per second per second.
So if you do this, have your calculator handy, pencil and paper, do the calculations for each scenario, then compare the numbers.
Next find a chart online that estimates the force required to sustain head injuries in a car crash. That is someones head hitting the dashboard, with the car taking the place of the person who slammed JonBenet, e.g. adding acceleration. These figures also come from dummies in test cars.
You will then have a range of Force figures, from JonBenet falling to the floor, to a car crash, then you can decide what was feasible.
In estimating the force applied I've left out Torque or Angular Motion, e.g. where JonBenet's head spins or twists as it moves through the air.
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