## Chapter 16

### Part 1: For the problem in the Teacher's Edition, page 380

Provide students with a copy of the Problem Worksheet (PDF file).

Ask the students the following questions to help them get started solving the problem:

**What does the HO scale of 1:87 mean?**(All measures on the model are 87 times smaller than on the actual car.)**How can you find the length of the HO scale model train to the nearest quarter inch?**(Multiply the length of the actual train, 75 feet, by 12 to find the length in inches. Divide the product by 87.)

You can also ask similar questions for O scale and N scale.

Answer:

HO scale: about 10 inches

O scale: about 18 inches

N scale: about 5 inches

### Part 2: Be an Investigator

A good time to do this investigation is after Lesson 3 on distance, speed, and time.

### Materials

- calculators (optional)

#### Introducing the Investigation

Introduce the investigation by reading aloud the assignment at the top of the first page of the Description of Investigation and Student Report (PDF file), by having one of your students read aloud the assignment, or by having the students read the assignment individually.

Put students in groups of two to four to work on the investigation.

#### Doing the Investigation

Ask the following questions to help the students get started doing the investigation.

**Of distance, speed, and time, what is known and what is not known?**(Time and distance are known and speed is not known.)**What formula would you use to find the speed?**(s = d ÷ t)

#### Answers:

**Indy 500 Winners**

Year | Winner | Time Converted to Decimal |
Speed (mph) |
---|---|---|---|

1990 | Arie Luyendyk | 2.686 | 185.981 |

1991 | Rick Mears | 2.833 | 176.457 |

1992 | Al Unser, Jr. | 3.718 | 134.477 |

1993 | Emerson Fittipaldi | 3.175 | 157.207 |

1994 | Al Unser, Jr. | 3.105 | 160.872 |

1995 | Jacques Villeneuve | 3.253 | 153.616 |

1996 | Buddy Lazier | 3.374 | 147.956 |

1997 | Arie Luyendyk | 3.424 | 145.827 |

1998 | Eddie Cheever, Jr. | 3.440 | 145.155 |

1999 | Kenny Brack | 3.264 | 153.176 |

2000 | Juan Montoya | 2.977 | 167.607 |

2001 | Helio Castroneves | 3.526 | 141.574 |

2002 | Helio Castroneves | 3.002 | 166.499 |

2003 | Gil de Ferran | 3.193 | 156.291 |

#### Student Report

The student report gives the students an opportunity to show what they have done.

#### Extending the Investigation

Have the students find the Indy 500 racecar driver with the fastest speed from 1990 on.