Mathematical Jerk Redux

 

I was scrolling through Twitter over the weekend and saw this pic: 

 with the phrase, “DON’T BE A …” right in front of it.

 

Yes! It took me a while to decrypt this (then I had to resort to google) but this is the mathematical expression of a Jerk.

 

No, not that kind of a jerk, not the kind the witty Twitter user was referencing. This kind of a jerk is what you’d experience if you were speeding up the highway and suddenly a force, say a huge gust of wind, pushes your vehicle quickly and unexpectedly to one side.

 

Now, “speed” here is a relative term. In physics, it’s called “velocity” because direction is generally though not necessarily indicated. Velocity is distance per time. It can be expressed in an equation relating these two variable. Throw some Calculus 101 in the mix, and you can obtain what’s called the second derivate of this equation. Since velocity is the change in distance over time, the second derivative represents the change in velocity over time. It’s called acceleration. Now, the third derivative (if you apply the derivative-obtaining technique to the second derivative) represents the change in acceleration over time. This is called “jerk.”

 

Like the beard-second, like the jiffy, math and physics has some interesting and humorous * terms. I had known about jerk from my calculus classes back in the early 90s, but had forgotten. However, I have never heard the technical terms “snap,” “crackle”, and “pop” in mathematics. Now I have and now you, if you have followed me up to this point, have also.

 

For the layman,

Acceleration is the change in velocity over time

Jerk is the change in acceleration over time

Snap is the change in jerk over time

Crackle is the change in snap over time

and

Pop is the change in crackle over time

 

And this is the Euler’s-honest truth!

 

Edit: After writing and publishing this, I see that I had done a similar blog post on it, here, on January 14, 2011, over thirteen years ago! It’s a great exhibit about the fickleness of memory. If you have a mathematical bent, I’d recommend reading that short post, ’cuz I particularly like the analogy used way back then.