In physics, pop is the sixth derivative of the position vector with respect to time, with the first, second, and third, fourth, and fifth derivatives being velocity, acceleration, jerk, snap (or jounce), and crackle, respectively; in other words, the pop is the rate of change of the crackle with respect to time. Pop is defined by any of the following equivalent expressions: The following equations are used for constant pop: where : constant pop, : initial crackle, : final crackle, : initial jounce, : final jounce, : initial jerk, : final jerk, : initial acceleration, : final acceleration,