Jerk or No Jerk At All

J=d³s/dt³

_{where s is distance, t is time, d/dt the derivative operation, and J is jerk.}

Then what does that mean? Where can that be used, possibly?

Rate of change of acceleration then...hmmm....not thought about it in those terms....

<wanders off humming>

And where would that be? How about the other issue to be raised: "What is significance of a negative value for Jerk"?

It seems the absolute values of jounce and jerk (RMS) may be more important to feel of the ride than the vector quantities.

Jerk is the rate of change of acceleration.

Consider a flexible object which due to its mass is compressed under acceleration. Jerk, or time rate of acceleration, is a measure of "flexing" of this flexible object. Any object made of multiple parts bonded together could subject to failure due to this flexing.

It's the reason bumpy roads tend to make parts fall off of old cars.

Consider the result of pounding on a granite boulder with a heavy hammer. It is known that when the rock breaks (specifically in that instant), there are sparks, and a release of ionizing radiation. Could it be that jounce, the fifth derivative of position against time is coupling our space-time with higher dimensions? Causing the ether to emit energy/matter? Or is there another explanation - no one seems to have a complete explanation to this at the present. Consider that cavitation in a fluid medium also has high order dynamics involved, and can produce flashes of light, etc. Some think these phenomena will lead the world of physics into an undreamed of abundance of energy.

(jerk and jounce), Newton already considered this within his treatises on motion.

So if you jounce a conducting coil (with tremendous vigor) in a magnetic field, is there more energy produced than from a smooth, fast motion? How to you compare the two. I believe the consensus opinion to be that which ever instance results in the cutting of more lines of the magnetic field will be the winner.

Beef, pork, chicken....

http://www.epicurious.com/recipes/food/views/grilled-jerk-chicken-106516

As others have mentioned, the Wikipedia article on Jerk.

This should not be confused with Steve Martin's movie:

If you jerk, you will go blind, and black hair will grow on your palms.

If you are hitting the top of your head (and it would seem so) due to bumpy road, why not try a different path? Or, you could go at a slower rate of speed, thus less J, or less dG/dt. If you continue to be hitting the top of your head, I must insist you stop it immediately, and seek professional help, possibly from a medical doctor for concussion.

The best way to deal with rubbles and ditches on a rough road (if you mean the ripples that form on a clay-gravel roadway due to vehicle suspension oscillations, rain, and washing out), is to make a drag that is heavy enough to fill in the low spots while dragging down the high spots. Drag the road after every precipitation event.

If this is an asphalt paved roadway, you must complain to local government authorities, and advise them, no eggs sunny side up (just omelets) until the road is corrected.

I'm virtually certain that you were not referring to the physics/calculus meaning of Jerk, nor the other implied meanings mentioned in posts 1-9...

The answer is yes: If you have shock absorbers on your vehicle that include permanent magnets and coils of wire, you can generate electric energy from the bouncing, and (with appropriate rectification and voltage regulation) charge/recharge a battery. Do note that this is NOT "free energy", it is simply recovering some of the energy expended by the normal propulsion system to move the vehicle along the rough road.

Yeah we got those....

Pothole power: This shock absorber turns vibrations and jolts from rough roads into electricity.

"Shock absorbers that generate electricity, which are being developed by Cambridge, MA-based Levant Power, can lower fuel consumption by 1.5 to 6 percent, depending on the vehicle and driving conditions. The system can also improve vehicle handling."

https://www.technologyreview.com/s/418859/electricity-generating-shock-absorbers/

https://en.wikipedia.org/wiki/Regenerative_shock_absorber

So could this shock be reversed into a powered applied reaction shock, if there were onboard jerk/jounce sensors to predict when would be a good time to counter react to road imperfections? Am I way off base with this idea?

Sounds like a viable idea to me, at least for very expensive vehicles that have a need for transporting their loads with absolute minimum vibration.

The sensors and electronics would have to be very fast, viewing the terrain just in front of each tire/wheel. I suspect it would consume a significant amount of energy.

Yes, but if one were transporting (not saying it is done or done legally either) nitroglycerin jars, as the driver (or anyone traveling within say a few miles of this load), I would want, no demand the very best in vibration and shock damping. I would also go very slow over an extremely low traffic road. Could you imagine what a bumper bump could do with a truckload of nitroglycerin jars? OMG.

I agree this thing would be an energy "sucker".

I would think you would have to have some sort of sensing wheels before your load-carrying wheels so you could use feed forward... There would be no way to produce a perfectly smooth ride using just feedback.

Just one more question: what happens to feed-forward control when the jouncing of the sensing wheels causes them to lost contact with road surface?

Some sort of sensing, yes. Wheels, I don't think so.

I was assuming some form of optical sensing, probably involving a laser or pulsed LED, in front of each wheel.

Now if you really want to guarantee a smooth ride under virtually all conditions, you'd also need sensors behind the wheels for reverse travel.

Are you complaining about our roads here in Pa??? Might want to duck here - not jerk.

Don't drive & Jerk, you'll end up in that ditch....

It's more dangerous than Texting while you drive.

question is: jerking to the left, to the right, up, down, on, off?

.....all around....

After reading your post and buddy Jame's, I am convinced, either you consumed excess dosage of alcohol or you might have a bad 'shroom meal.

Once when living in Northern Oklahoma, my wife drove a group of Hell's Angels jerking in a circle, out in broad daylight by a major intersection in the little town. I thought she was joking, but she persisted in claiming this story as real. Absolutely mind boggling what goes on, even in small towns in the U.S.A. (United Skates of Arses).

Would it have been less offensive had they only been jouncing in a circle? What about just accelerating in a circle, or going in a circle?

I know this would be censored if they were twerking in a circle, but bikers don't do that.

As I implied in an earlier post, I'm sure many of those reading this thread have no idea whatsoever of the meaning of jerk when used as a personal verb.

That is apparently a good thing as well.

As a side note, I have heard of husbands taking their pregnant wives for a ride in the farm truck over some really rough ground in late weeks of the term, to "assist" her along with going into labor. I guess some bumpy roads are a necessary evil.