** ****Kinematics** is the science of describing the motion of objects using words, diagrams, numbers, graphs, and equations. Kinematics is a branch of mechanics. The goal of any study of kinematics is to develop sophisticated mental models that serve to describe (and ultimately, explain) the motion of real-world objects.

Definition Provided by Physics Classroom

Kinematics has two subsets the classical "static" kinematics and then the post calculus "dynamic" kinematics. Both study the motion of an object and use mathematical equations to predict the location, speed, and acceleration of that object at some future time. The difference is in the initial conditions and the level of mathematical complexity used for these predictions. What they have in common is vocabulary.

Review: What you should already know

**Position**: The location of an object at a single moment in time

**Velocity**: The change in an objects position over a period of time. That is an object starts at one position, and then at some time later the position has change. The velocity is by how much the position changed divided by the amount of time it took.

Change in position / Change in time = Velocity (m/s)

Example: imagine that you throw a ball with another student watching with a stop watch. The student starts the stop watch the instant the ball leaves your hand. two second later the student stops the stopwatch and the position of the ball is recorded as being 20 meters away. The velocity would be

change in position (20 m) / Change in time (2 s) = 10 m/s

The other thing that needs to be recorded when working with velocity is direction. Weather the object is traveling north, east south or west, or using the x,y and Z direction, the direction the object is heading must be recorded.

**Acceleration**: The change in an objects velocity over a period of time. That is an object is moving at some velocity and at some time later the velocity has change. The acceleration is by how much the velocity has change divided by the amount of time it took.

Change in velocity / Change in time = acceleration (m/s/s)

Example: In the driver seat there there are three controls that will produce an acceleration

1. The accelerator pedal push down on this and the car goes faster and faster, the change in position the car experiences for every second (the amount of ground it covers if you will) increases, there for the car is accelerating.

2. The brake pedal push down on this and the car goes slower and slower, the change in position the car experiences for every second (the amount of ground it covers if you will) decreases, there for the car is accelerating. Important to note that acceleration is only concerned is it the velocity is change not weather it's going faster or slower.

3. The steering wheel, Turn this and the direction the car changes. How is this an acceleration? Velocity differs from speed in that velocity has to have a direction (with the exception of zero velocity) so if the direction changes so does the velocity.

The remaining terms are not that important so I wont spend much time on them

**Jerk**: The change in an objects acceleration over a period of time. That is an object has an acceleration and at some time later the acceleration has change. The jerk is by how much the acceleration has change divided by the amount of time it took.

**Snap**: The change in an objects jerk over a period of time. That is an object has a jerk and at some time later the jerk has change. The snap is by how much the jerk has change divided by the amount of time it took. Snap is followed by **crackle** then **pop**, who said physicists don't have a sense of humor.

Now here is the difference between static and dynamic kinematics

Static: Classic (pre-calculus) kinematics

Position: Can change or stay the same

Velocity: Can change or stay the same

Acceleration: Is always constant

Jerk: is always zero

Snap: is always zero

Dynamic: post-calculus kinematics

Position: Can change or stay the same

Velocity: Can change or stay the same

Acceleration: Can change or stay the same

Jerk: Can change or stay the same

Snap: Can change or stay the same

For all classes we will only consider classic kinematics when solving problems