Physical Science
Graphing Little Dudes
Suppose something is moving. If you collect corresponding clock readings(time) and position measurements (distance), these numbers form ordered pairs that can easily be graphed. Consider the various little dudes shown below. They exist and move along a sidewalk marked in 1 meter increments. We are given snapshots of them at regular time intervals. Follow the instructions below to construct and analyze position-time graphs. Answer the questions as you go.
Complete the data table to the right based on the diagrams of Walking Dude below.
Clock Reading
t (seconds)
Position
d (meters)
0
0
2
4
4
9
6
13
8
16
Using the data from your table plot the points for Walking Dude.
What assumptions would we have to make about Walking Dude’s motion if we were to connect the points with a straight, continuous line?
Make the assumption and connect the points. Label the line “Walking Dude”.
The equation for finding speed is:
Rewrite the equation for speed, substituting change in position (d2 - d1) for distance and change in time (t2 - t1) for time:
This is the greek letter delta Δ. It means change.
What does Δd mean? What is Δd for Walking Dude for 5s to 8s?
What does Δt mean? What is Δt for Walking Dude for 5s to 8s?
Use your equation to find the speed of Walking Dude:
On a graph slope can be found by rise over run. On our graph what quantity represents rise? What quantity represents run?
What does the slope of a position-time graph tell you about the motion of an object?
Use your graph to plot the motion of both of the little dudes shown below. Label the lines with the names of the dudes/dudettes.
What would a line with a slope that was less steep than Walking Dude’s mean?
What would a line with a negative slope mean?
Would a completely vertical line be possible? Why or why not?
Draw and label a line for Walking Dude II, parallel to the line for Walking Dude but starting at (0s, 8m). What is the difference between Walking Dude and Walking Dude II?
Credit: Dean Baird, The Book of Phiz.
