# Velocity, acceleration, jerk, snap, crackle, pop, stop, drop, roll....

• sassafrasaxe
In summary, the conversation discusses the concept of cause and effect in motion, specifically how acceleration leads to changes in velocity and subsequently other physical properties such as jerk, snap, crackle, pop, stop, drop, and roll. The question is raised whether there is ever a true beginning to motion, as each change seems to be caused by a lower level change. This leads to a discussion about the fundamentals of physics and the role of differential equations in describing motion.
sassafrasaxe
Edit: I see this was discussed in the related thread sorry for a repost.
If acceleration causes a change in velocity, and jerk causes a change in acceleration, snap causes a change in jerk, crackle causes a change in snap, pop causes a change in crackle, stop causes a change in pop, drop causes a change in stop, roll causes a change in drop... and there are infinitely more layers?
Then if every change is causes by a lower level change, is there ever a beginning to any motion? What is actually happening when things begin moving? Sorry for the dumb question.

sassafrasaxe said:
If acceleration causes a change in velocity...
Acceleration is the change in velocity, not a cause of it that happens before.

Most of physics is captured by first and second order differential equations. For instance, the second derivative of position is acceleration which typically depends on position, velocity and mass.

vanhees71

## 1. What is the difference between velocity and acceleration?

Velocity refers to the rate of change of an object's position over time, while acceleration refers to the rate of change of an object's velocity over time. In other words, velocity tells us how fast an object is moving and in what direction, while acceleration tells us how much an object's velocity is changing.

## 2. What is jerk?

Jerk is the rate of change of an object's acceleration over time. It is a measure of how quickly an object's acceleration is changing. A high jerk value indicates that an object is experiencing a large and rapid change in acceleration.

## 3. What are snap, crackle, and pop in relation to motion?

Snap, crackle, and pop are higher-order derivatives of an object's position, velocity, and acceleration, respectively. They represent the rate of change of jerk, snap being the fourth derivative, crackle being the fifth derivative, and pop being the sixth derivative. These terms are used to describe the smoothness of an object's motion.

## 4. How do you calculate velocity and acceleration?

Velocity can be calculated by dividing the change in an object's position by the change in time. Acceleration can be calculated by dividing the change in an object's velocity by the change in time. Both velocity and acceleration can also be calculated using their respective equations: v = u + at (for velocity) and a = (v-u)/t (for acceleration), where u is the initial velocity, v is the final velocity, and t is the time interval.

## 5. Why do objects stop, drop, and roll?

Objects stop, drop, and roll due to the forces acting on them. When an object is at rest, the forces acting on it are balanced. However, when an unbalanced force is applied, such as gravity, the object will start to move (drop) and accelerate (roll) due to the unbalanced force. When the force is removed, the object will eventually come to a stop due to the opposing forces of friction and air resistance.

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