A | B |

frame of reference | a system of objects that are not moving with respect to one another |

relative motion | movement in relation to a frame of reference |

distance | the length of a path between two points |

vector | a quantity that has magnitude and direction |

resultant vector | the vector sum of two or more vectors |

speed | the ratio of the distance an object moves to the amount of time the object moves |

average speed | the total distance traveled divided by the time it takes to travel that distance |

instantaneous speed | the rate at which an object is moving at a given moment in time |

velocity | the speed and direction in which an object is moving |

acceleration | the rate at which velocity changes |

free fall | the movement of an object toward Earth solely because of gravity |

constant acceleration | a steady change in velocity |

linear graph | a graph in which the displayed data form straight-line parts |

nonlinear graph | a curve connect the data points that are plotted |