Homework 4:
Due Wednesday 6/18/14
1. It took me 21 seconds to run a 100 meter race. I ran 60 meters in the first 7 seconds,
30 meters in 2nd 7 seconds, and 10 meters in the last 7 seconds.
• Plot these points on a graph.
• What was my average speed during each 7 second interval?
• Was my speed most likely increasing or decreasing?
• What was my average speed overall?
• Could you beat me in a race?
2. What is the average rate of change of y = 2x on the interval [0, 5]? How about on
[5, 10]?
3. What is the average rate of change of y = 2x + 3 on [−4, −1]? How about on [1, 2]?
Why should this answer not surprise you?
4. Do problems a and b on page 33 of ”Example 17: The Tortoise and the Hare” in your
book.
Hint: Get an equation that expresses the distance traveled by the hare in terms of
seconds in time. Do the same for the tortoise. The distance of both animals is changing
at a constant rate so both equations should be lines. What is the rate of change/slope
for each animal? What is the Y-intercept/initial distance for each animal? From this
information you should be able to get both equations. Once you have both equations
subtract one from the other to answer part a. I will let you figure out part b.
The book continues on to explain a solution to the problem. Feel free to read through
this for help. Also feel free to work together.
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