## Item FM067003: Use of tables of speed versus time, and information about forces acting on an object, to determine the object's speed at various times.

An object is moving forward and no forces are acting on it. Every second, the object's speed is recorded. When the clock reads 0 seconds, the object's speed is 10 miles per hour (mi/hr). When the clock reads 2 seconds, a force begins to push the object forward. The force continues to act until the clock reads 4 seconds and then the force stops acting.

Clock → | 0 seconds | 1 second | 2 seconds | 3 seconds | 4 seconds | 5 seconds | 6 seconds |

Row A | 10 mi/hr | 9 mi/hr | 8 mi/hr | 8 mi/hr | 8 mi/hr | 7 mi/hr | 6 mi/hr |

Row B | 10 mi/hr | 10 mi/hr | 10 mi/hr | 11 mi/hr | 12 mi/hr | 13 mi/hr | 14 mi/hr |

Row C | 10 mi/hr | 10 mi/hr | 10 mi/hr | 11 mi/hr | 12 mi/hr | 12 mi/hr | 12 mi/hr |

Row D | 10 mi/hr | 11 mi/hr | 12 mi/hr | 13 mi/hr | 14 mi/hr | 15 mi/hr | 16 mi/hr |

Which row of the table could be a correct representation of the object's speed between 0 seconds and 6 seconds? Assume that if a change in speed has occurred, the change is shown in the table.

- Row A
- Row B
- Row C
- Row D

- Distribution of Responses

- Students Responding Correctly

Group | Correct | Total | Percent |
---|---|---|---|

Overall | 692 | 1796 | 39% |

Grades | |||

6–8 | 383 | 1129 | 34% |

9–12 | 304 | 658 | 46% |

Gender | |||

Male | 340 | 837 | 41% |

Female | 332 | 912 | 36% |

Primary Language | |||

English | 614 | 1582 | 39% |

Other | 62 | 179 | 35% |

- Disciplinary Core Ideas
- PS2.A The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion.

PS2.A Newton's second law accurately predicts changes in the motion of macroscopic objects.