| A | B |
|---|
| Accelerate | to increase speed or change direction |
| acceleration | the change of speed over time |
| average speed | how fast something moves over a certain distance |
| conceptual model | a written description or diagram based on ideas and observations that are used to describe how a process or object works; |
| deceleration | occurs when change in speed, or acceleration, is in the negative direction. |
| dependent variable | the variable in an experiment that changes in response to choices made by the experimenter; this variable is plotted on the y-axis of a graph. |
| free fall | the acceleration of a falling object under the influence of the Earth’s gravitational force. |
| graphical model | a model that shows the relationship between two variables on a graph so that the relationship is easily seen and understood. |
| gravity | the attractive force that exists between any two objects that have mass. |
| independent variable | the variable in an experiment that is manipulated by the experimenter and that causes changes in the dependent variable in the experiment; this variable is plotted on the x-axis of a graph. |
| instantaneous speed | the speed of an object at a specific point in its journey. |
| physical model | models that are made of materials and that can be touched and measured; engineers construct scale physical models to test a structure before building it. |
| scientific model | a method of representing the relationship between variables |
