A mechanical engineer is testing the amount of force needed to make a spring
stretch by a given amount. The force y is measured in units called
then using the equation, why the relationship is proportional.
Unit 3 Performance
1.
Newtons, abbreviated N. The stretch x is measured in centimeters,
Her results are shown in the graph.
a. Write an equation for the line. Explain, using the graph and
Force (N)
32
o
8 10
Stretch (cm)
b. Identify the rate of change and the constant of proportionality.
c. What is the meaning of the constant of proportionality in the context
of the problem?
d. The engineer applies a force of 41.6 Newtons to the spring. Write and
solve an equation to find the corresponding stretch in the spring.
2. A math tutor charges $30 for a consultation, and then $25 per hour. An
online tutoring service charges $30 per hour.
a. Does either service represent a proportional relationship? Explain.
b. Write an equation for the cost c of h hours of tutoring for either
service. Which service charges less for 4 hours of tutoring? Show
your work.