Applications
Normally concerning forces, speed and acceleration are used for analysis. For example, the "jerk" produced by falling from outer space to the Earth is not particularly useful given the gravitational acceleration changes very slowly. Sometimes the analysis has to extend to jerk for a particular reason.
Jerk is often used in engineering, especially when building roller coasters. Some precision or fragile objects — such as passengers, who need time to sense stress changes and adjust their muscle tension or suffer conditions such as whiplash — can be safely subjected not only to a maximum acceleration, but also to a maximum jerk. Even where occupant safety isn't an issue, excessive jerk may result in an uncomfortable ride on elevators, trams and the like, and engineers expend considerable design effort to minimize it. Jerk may be considered when the excitation of vibrations is a concern. A device that measures jerk is called a "jerkmeter".
Jerk is also important to consider in manufacturing processes. Rapid changes in acceleration of a cutting tool can lead to premature tool wear and result in uneven cuts. This is why modern motion controllers include jerk limitation features.
In mechanical engineering, jerk is considered, in addition to velocity and acceleration, in the development of cam profiles because of tribological implications and the ability of the actuated body to follow the cam profile without chatter.
Read more about this topic: Jerk (physics)