Math 101.02
In-Class assignment #1
Due 12:01 p.m. Friday, 15 January 1999
On a separate piece of paper, answer the following questions. Neatness
counts.
From The Official Dr. Science Big Book of Science:
Q: Many people realize they can tell the temperature by counting the chirps a cricket
makes. But how does the cricket know what temperature it is?
A: While you're on the verandah swatting mosquitoes and complaining to your friends
about how hot it is, the cricket is sitting in air-conditioned comfort watching the six o'clock news.
Out of boredom, perhaps, or a genuine need to give us information, the cricket communicates this
weather information to you. The cricket will also click out, in Morse code, the final sports scores
and national headlines, even such phrases as "Now this," "Film at eleven," and "Our White House
correspondent filed this report." Some scientists call the cricket "the Walter Cronkite of the
insect world," which is accurate but somewhat silly. After all, you've never seen Walter Cronkite
rubbing his legs together. At least I hope you haven't.
1. Suppose that on your last camping trip to Canada you noticed that when the temperature was
10° Celsius (which you know because you were listening to the radio) the cricket in your tent
chirped 50 times in a minute. Later that afternoon when the temperature was 25° Celsius,
you counted 148 chirps in a minute.
a. Write a linear function (equation) that determines the temperature, t, based on the number
of chirps per minute, N, your little friend, Jimminy, makes.
b. What is the slope of this equation?
i.
Interpret this number.
c. What is the N-intercept of this equation?
i.
Interpret this number.
ii.
Does it make sense?
d. What is the temperature if Jimminy chirps 100 times in a minute?
e. If the temperature is 17° Celsius, how many times should you expect Jimminy to chirp?
2. Now suppose that upon your return to CWU you wanted to tell your roommates about your
outing. Unfortunately, being Americans, your roommates have no idea how cold or hot 10°
Celsius is. So, you decide to convert your Celsius measurements into Fahrenheit.
You know that water freezes at 32° Fahrenheit and at 0° Celsius. You also know that water
boils at 212° Fahrenheit and at 100° Celsius.
a. Write a linear function (equation) that determines the temperature in Fahrenheit, F, given
the temperature in Celsius, C.
b. Use the function derived in 2.a to convert 10° Celsius and 25° Celsius into degrees
Fahrenheit.
c. Using the temperatures derived in 2.b, answer question 1.a - 1.e.