Luttrell 2012
125
Name: ______________________
Date: _____
8L – Quadratic Word Problems
A quadratic equation can be recognized by the shape of the data when plotted. Or ma
y
be an
equation was given and it was in the form
y
=
ax
2
+
bx
+
c
where a ≠0. If you need to e
x
trapolate
or interpolate (predict) some values, it is best to find the equation first. Then using the equation,
the prediction of the needed value should be accurate.
Solve:
1. A ball is kicked so that it lands 50 feet awa
y
3 seconds later. The height of the ball at an
y
given moment is found b
y
h
= -12
x
2
+ 36
x.
According to the equation, what is the ma
x
imum
height the ball travelled?
2. Wind chill temperature is given b
y
the formula
C
w
F
= −
+
1
6
2
, where
C
is the wind chill
temperature,
w
is the wind speed in miles per hour, and
F
is the Fahrenheit temperature in still
air. On Jul
y
12, the wind speed was 15 mph and the still air was 88
°
F. What was the wind chill
temperature for that da
y
? Which variable has greater effect on
C
? E
x
plain
y
our conclusion.
3. Carbon Dio
x
ide emissions were found to be increasing since 1975. The following equation
has been simplified to make calculations easier,
x
represents the number of
y
ears since 1975 and
y
represents CO
2
measured in parts per million: y = 0.005x
2
+ x + 300. What would
y
ou e
x
pect
for the
y
ear 2006?
4. The horsepower required to overcome wind drag on an automobile is appro
x
imated b
y
H = 0.01s
2
+ 0.01s – 0.1
where s is the speed of the car in miles per hour. What is the speed
of the car when the horse power is 2?
