# Is impulsive tension called jerk? [closed]

Jerk is derivative of acceleration, is impulsive tension also the same. Or there is nothing like impulsive tension

• Would you give a bit more context to the question, for example a case you are considering or what do you mean by "impulsive tension", that will help people attempting to help you – ohneVal Sep 13 '19 at 7:50
• you corrected the title, but not the question. Also explain what do you mean – lurscher Sep 13 '19 at 9:49

The English word "jerk" has been co-opted in physics to refer to the derivative of acceleration i.e. the third derivative of position with respect to time. Confusingly, this has very little to do with the everyday English meaning of the word "jerk" which is a short, sharp pull. The physics "jerk" is not necessarily either short or sharp.

For example, a particle whose position at time $$t$$ seconds is $$x(t)=t^3$$ metres has a velocity $$\displaystyle v(t) = \frac{dx}{dt}=3t^2$$ metres per second, an acceleration $$\displaystyle a(t) = \frac{dv}{dt}=6t$$ metres per second$$^2$$, and a constant "jerk" $$\displaystyle j = \frac{da}{dt}=6$$ metres per second$$^3$$.

• I find that the practice of calling $da/dt$ by the name "jerk" is not nearly as fully established as the vast majority of other terms in physics. Therefore I would recommend that a student learn that it is used, but aim to avoid it themselves unless they really need a word for rate of change of acceleration. – Andrew Steane Sep 13 '19 at 11:26
• @AndrewSteane It was rarely used in my experience, but as far as I'm aware it is definitely still the proper term, and was always referred to as such in my experience. Definitely more so than "snap, crackle, and pop", for example. They are just so rarely used that they never really become "established", even if it's the right word. – JMac Sep 13 '19 at 14:00
• In horizontal mass transit vehicles 'jerk' tends to thow people off there feet, whereas they can compensate for acceleration. So the designers control the rate of change of acceleration. – user45664 Sep 13 '19 at 17:17