Jerk is the third derivative of displacement with respect to time. It is also the derivative of acceleration with respect to time.
Questions tagged [jerk]
114 questions
51
votes
3 answers
What is the meaning of the third derivative printed on this T-shirt?
Don't be a $\frac{d^3x}{dt^3}$
What does it all mean?
VodkaTampons
45
votes
17 answers
Why does one experience a short pull in the wrong direction when a vehicle stops?
When you're in a train and it slows down, you experience the push forward from the deceleration which is no surprise since the force one experiences results from good old $F=m a$. However, the moment the train stops one is apparently pulled…
Tobias Kienzler
- 6,950
29
votes
7 answers
What would happen if $F=m\dot{a}$?
What would happen if instead of $F=m \frac{d^2x}{dt^2}$, we had $F=m \frac{d^3x}{dt^3}$ or higher?
Intuitively, I have always seen a justification for $\sim 1/r^2$ forces as the "forces being divided equally over the area of a sphere of radius…
TROLLHUNTER
- 5,341
27
votes
21 answers
What happens when a car starts moving? The last moment the car is at rest versus the first moment the car moves
Imagine a car that's at rest and then it starts moving. Consider these two moments:
The last moment the car is at rest.
The first moment the car moves.
The question is: what happens between these 2 moments? It might sound like a silly question and…
fab
- 381
22
votes
8 answers
What happens if a slow train hits you?
It's funny, I used to wonder this at school many years ago. For the purposes of discussion, imagine there is a big (very massive) cube that slides towards you as you're sitting on the floor. It doesn't move fast, perhaps (say) walking pace. Would it…
22
votes
1 answer
What came first, Rice Crispy or "Snap," "Crackle," and "Pop"?
The fourth, fifth, and sixth derivatives of position are called "Snap" "Crackle" and "Pop". What came first, the rice crispy characters, or the physics units?
Sponge Bob
- 594
20
votes
5 answers
Applying energy and momentum conservation to the problem of pulling a bent carpet at a constant speed
Consider this system.
A long, thin, pliable carpet is laid on a floor. One end of the carpet is bent back and then pulled backwards with constant speed $v$, just above the part of the carpet which is still at rest on the floor. What is the…
Hans
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16
votes
5 answers
What is the best path for a given initial and final state?
I am trying to calculate an efficient acceleration curve given starting and final positions and velocities. I'm assuming no friction, and that the acceleration can be applied in any direction at any time.
Given:
$p_0$ = starting position
$v_0$ =…
generesque
- 163
15
votes
5 answers
How do I calculate the distance a ship will take to stop?
I am a River Pilot and drive ships for a living. These ships are very large and range up to 160,000 Metric Tons. I am trying to figure out how to calculate the distance to stopping. I have a basic understanding of the physics 101 equations, but I…
wayofthefuture
- 281
15
votes
5 answers
How to brake 'beautifully'?
Sometimes when I'm driving my car, I play a "game" against myself in which I try to minimize the deceleration felt by passengers (including myself) while still braking in a reasonable short space. I do know that the deceleration felt is not only…
Alpha
- 253
15
votes
3 answers
Is it possible to have a rate of change of acceleration?
I know this may seem a weird question, but it always bothers me. My physics book (Resnick,Halliday,Walker), and also various sites never say anything beyond acceleration.
But when a moving body is being acted by a variable force , its acceleration…
user36790
13
votes
3 answers
Why don't we consider jerk in physics classes?
When I got more into physics, I started asking myself if just like acceleration represents the growth of speed, something else could also represent the growth of acceleration itself. And it came that is exists and is called jerk. Before I thought…
Devian Dover
- 241
11
votes
3 answers
Upper limits for jerk and higher derivatives in physics
Is there an upper limit for jerk in physics? What about higher derivatives?
A consequence of special relativity is that no material body can reach or exceed the speed of light in vacuum (due to the relativistic mass increase, or the Lorentz…
Cristian Dumitrescu
- 1,049
11
votes
2 answers
Kinematic equation as infinite sum
I'm not sure exactly how to phrase this question, but here it goes:
$v=\dfrac{dx}{dt}$ therefore $x=x_0+vt$
UNLESS there's an acceleration, in which case
$a=\dfrac{dv}{dt}$ therefore $x=x_0+v_0t+\dfrac{1}{2}at^2$
UNLESS there's a jerk, in which…
10
votes
3 answers
Is there any case in physics where the equations of motion depend on high time derivatives of the position?
For example if the force on a particle is of the form $ \mathbf F = \mathbf F(\mathbf r, \dot{\mathbf r}, \ddot{\mathbf r}, \dddot{\mathbf r}) $, then the equation of motion would be a third order differential equation, what will require us to know…
Andrey S
- 1,066