Equations of Lines
Fellow: Brooke Odle
Teacher: Maria Sanchez
School: St. Vincent Academy
Date: January 9, 2012
Objectives
 Write and graph equations of lines
 Vernier activity:
 Record distance versus time data for a person walking at a
constant rate.
 Analyze the data to extract slope and intercept information.
 Interpret the slope and intercept information for physical
meaning.
Equations of Lines: A review
 Linear Equation:
 An equation whose graph is a straight line
 Y-intercept:
 The y-value of the point where a line crosses the y-axis
 Slope-intercept form:
 The form of a linear equation written as y = mx + b,
 Where m = slope and b = y-intercept
Vernier Activity: Walk the Line
 When one quantity changes at a constant rate with respect to
another, they are linearly related.
 In math, we describe this relationship by defining a linear
equation.
 In real-world applications, some quantities are linearlyrelated and can be represented by using a straight-line graph.
 Ex: Distance versus time
Vernier Activity: Walk the Line
 Objectives:
 Record distance versus time data for a person walking at a constant
rate.
 Analyze the data to extract slope and intercept information.
 Interpret the slope and intercept information for physical meaning.
 Materials:
 Laptop
 Vernier Logger Pro software
 Vernier Lab Pro
 Motion Detector
 Volunteer
Data Table
Y-intercept b
Optimized slope m
Optimized line equation
x1,y1
x2,y2
Slope
Regression line equation
How does this value compare with the
slope you found by trial and error?
Follow-up Questions
1.
How do the values of the slope and intercept as determined
by Logger Pro compare to your earlier values? Would you
expect them to be different?
2.
Slope is defined as change in y-values divided by change in
x-values. In this activity, slope represents a change in
________ divided by a change in ________.
3.
What are the units of measurement for slope in this
activity?
Challenge Question
 The y-intercept can be interpreted as the starting position or
the starting distance from the Motion Detector. What does
the slope represent physically?
 Hint: Consider the units of measurement for the slope
you described in the previous question.