Do you have proof for that, or is this like audiophiles asking for gold connectors because "they make the sound better"?
This is in fact an issue for the designers of controls for mechanical systems. I learned about it in Process Control class, albeit 40 years ago.
If older cars had a higher differential, you’d need to let up more as the brake finally locks up.
There's mechanical braking assistance (not just ABS) which means pressing the same pedal distance may produce different breaking strength depending on the speed at which the pedal is pressed; e.g pressing hard triggers force assistance from, say, a vacuum reservoir that reuses engine pump loss, which means conversely pressing lightly for a normal stop does not need to exert as much pressure, hence an eased in stop.
Also with more stable vehicles with better chassis, suspension, and overall balance, I feel like rear braking has been tuned upwards over time, making for a more stable stop: notice how lightly pulling the handbrake has a straight-rolling car "sitting" instead of "diving". More consistent use of disc brakes instead of drums on the rear end certainly helps, as well as the ability for the vehicle to remain stable even when braking while in a turn.
Regarding brake friction itself, I can think of at least one major change: the ban of materials such as copper or asbestos in brake pads.
Some of the German marque factory pads have exceptional initial bite, coupled with exceptional high levels of dust.
Your muscles are pretty good at applying a constant force (or responding to a constant acceleration). Hold your arm out straight: it's no effort to keep your arm still and counteract the force of gravity. Now imagine gravity varies quickly and randomly between 0.5g and 2g. I guarantee your arm won't stay still.
The same prinicple applies on a bus or in a car, except this time the forces are smaller, and it's your neck keeping your head still!
> (...) jerk, snap and crackle. Turns out if you minimize those, you get a far more comfortable ride.
e.g. https://iopscience.iop.org/article/10.1088/1361-6552/aba732
Ever experienced that a bus is braking (near-constant deacceleration), and people seem fine; but then the bus comes to a halt and thus stops deaccelerating, and people suddenly fall on the floor?
I think at least the derivative or acceleration is important for how well people can compensate. Not sure about higher derivatives though.
But, the bus has a non-constant kinetic energy (going up with the velocity*velocity, down as velocity goes down.)
So, you're actually producing a non-linear acceleration. This is jerk, but you can also think of it as just a non-linear acceleration and people are reacting to the fact it's not at all near constant deacceleration, and this is most noticable as velocity hits zero.
So, yes, it's jerk, but no, I think it can be intuitively better understood with pure acceleration terms and no jerk needed
At macroscopic scales, I’m not aware of exactly instantaneous acceleration, since you would need some time to “sync” the movement of each atom in the object. But some processes will of course look instantaneous at any given time scale.
Figure 4-3 in https://www.ibiblio.org/apollo/Documents/lvfea-AS506-Apollo1... shows this for Apollo 11.
There is an interesting Δa/Δt while fuel is consumed and mass changes.
There are discontinuities to the graph when engines are shut down and stages decoupled.
Over a macro scale, it’s discontinuous, of course.
But, checkout Zeno's paradox for more on your philosophical questions
The proof is that roughly 100% of cars have components designed to limit this.