In this unit we will be using some new vocabulary and math techniques to describe motion. In the first part of the unit we will do this all in one dimension. In the second part we will add the concept of vectors to describe motion in two dimensions. All we are concerned with at this time is describing motion, not the causes of motion. The causes of motion will come later.

Velocity: Velocity is the slope of the displacement vs. time graph. Many people think of velocity as speed. The major difference is that velocity has direction as part of the measurement, either expressed ( 20 m/s North) or implied (falling at 3.2 m/s). For people with higher math skills, velocity is the rate of change in position or the first derivative of position. Velocity in the metric system is measured in meters/second and the symbol in the math equations we use is

Acceleration: Acceleration is the slope of the velocity vs. time graph. Acceleration always has direction although in common usage people often us deceleration as a term for negative acceleration. It is the second derivative of position or the rate of change of velocity. Acceleration is measured in meters/second/second (meters per second squared) and the symbol in the math equations we use is

Jerk: The jerk is a physics quantity that is seldom used in formal physics but the concept is often used in general society. The jerk is the slope of the acceleration vs. time graph. Because any measurement errors are already greatly magnified in acceleration, calculating a value for jerk often results in errors that are greater than the values calculated.

Time: Something that we all know about but is difficult to define. In classical physics the change in time is constant. We may define the beginning of time how ever we want but time does not stop, speed up, slow down or end. Time in the metric system is measured in seconds and the symbol in the math equations we use is

Slope: Many people define slope as "the rise over the run". While this is a true statement I think it loses much of the beauty of the math. Slope as a formula is calculated as (y

Independent variable: In this section of physics, time is

Dependent variable: The variables that are determined by something else. In the case of kinematics the independent variables depend on time. Where you are, how fast you are moving, how your velocity is changing all depend on time, the time does not depend on you being somewhere (can you imagine time ceasing to exist because you weren't in your assigned seat during 1st block?). The dependent variable is always put on the y axis.

The Physics Classroom

Human Kinematics - Future doctors, atheletes, nurses, physical therapists take note!

Kinematics Simulation at Thinkquest

Relative Motion Simulator Frame of Reference Demonstrated