A rate describes how much one variable changes with respect to another. Rates are often used to describe relationships between time and distance. When an object or person moves at a constant rate, the relationship between distance and time is linear. Note 11
Achilles is going to race against a tortoise, who moves at only 1 mile per hour. To make the race fair, the tortoise gets a head start of 32 miles.
a.
Write an equation describing the relationship between distance and time for the tortoise.
b.
Enter the tortoise's equation into a spreadsheet.
c.
How long will it take for Achilles to catch up to the tortoise?
Video Segment In this video segment, participants use a spreadsheet program to answer Problem C2. Watch this segment after you have completed Problem C2. If you get stuck on the problem, you can watch the video segment to help you.
Could the participants have answered Problem C2 using a recursive rule?
You can find this segment on the session video, approximately 17 minutes and 56 seconds after the Annenberg Media logo.
Problem C3
Make a single graph that shows the progress of Achilles and the tortoise. Where do the two lines cross?
Problem C4
What is the relationship between the points where the lines cross and Achilles passing the tortoise?
Problem C5
Which of the two lines in Problem C3 represents a proportional relationship? How do you know?
Suppose that two people were traveling a distance of 100 miles at the same speed, and the first person got a head start of 25 miles. When would you expect them to be at the same point? What does this tell you about their distance graphs? Note 13
