| A | B |
|---|
| An object is in motion if.... | its distance from another object is changing |
| a place or object used for comparison to tell if something is in motion | reference point |
| A change in an object's position relative to a reference point is called... | relative motion |
| The system of measurement used all over the world is called... | International System of Units, or SI |
| The SI unit of length | meter |
| If you know the distance an object travels in a certain amount of time, you know its... | speed |
| the speed equation is... | speed = distance/time |
| total distance divided by total time is... | average speed |
| The rate at which an object is moving at a given instant in time is... | instantaneous time |
| distance traveled per unit of time | speed |
| What 2 things do you need to know to determine an object's velocity? | speed and direction |
| speed in a given direction | velocity |
| To show the motion of an object on a line graph, you plot what 2 things? | distance vs time or speed vs time |
| the steepness, or slant, of a line on a graph | slope |
| A horizontal line on a distance vs time graph shows what? | distance did not change - object not moving |
| when the speed of an object does not change, the object is moving at a... | constant speed |
| Why can't you tell that the earth's plates are moving? | They move very slowly. |
| the rate at which velocity changes | acceleration |
| What is the theory of plate tectonics? | Earth's plates move very slowly in various directions. |
| Acceleration involves a change in... | speed or direction |
| To determine the acceleration of an object, you must calculate the change in... | speed per unit of time |
| the rate at which velocity changes | acceleration |
| A moving roller coaster accelerates because... | it is constantly changing direction |
| On a speed vs time graph, a straight line shows acceleration is... | constant |
| unit of acceleration | meters per second per second (m/s2- with 2 as an exponent) |
| A word for negative acceleration is... | deceleration |
| formula for acceleration | acceleration= (final speed minus initial speed)/time |
| first part of the 3-step method | list what you know and what you want to find out |
| 2nd part of the 3-step method | write the formula you will use, then plug in the numbers (what you know) |
| 3rd part of the 3-step method | solve the formula |
