Name (s): ___________________________________________________________ Hr. ____
Today, let’s explore our position-time, velocity-time, and acceleration-time graphs using a computer simulation:
Open up the following webpage:
http://phet.colorado.edu/en/simulations/category/physics/motion
Scroll down if needed to find the simulation called ‘The Moving Man.’ Click on this.
On the next screen click ‘Run Now.’
At this point, you may see a screen requiring a username and
password. You can click, ‘Cancel’ here.
The program should now open and you will see this screen:
Play around with the settings:
 You can move the man by hand.
 Or, you can put a value in for position, velocity, and time
 Or, you can move the slider.
 Notice that you can record your motion for playback. Play around with this, too.
Spend some time playing with this screen, changing each variable independently to see what happens to the man as
you change his position, velocity, and acceleration.
The Moving Man computer simulation, p. 1
Now on the upper left, click the tab, ‘Charts.’ You will now see something along these lines:
1. Change the values to the following on the left picture and then hit,
‘play.’ Look at your graphs. You should get a diagonal on your
position-time graph and then a horizontal on your velocity-time graph.
Here are mine.
2. Change your velocity to higher and lower values and then also make the velocity negative and check out your
graphs. What happens to the walking man if you make the velocity negative? Make sure you understand the graphs
you see.
3. Now reset everything and keep the position = 0 and the velocity = 0 but change the acceleration to +1. You should
see a getting faster parabola on your position-time graph, a diagonal on your vt, and a horizontal on your accelerationtime graph. Verify this.
4. Now play around with the simulation and put different values in for your position, velocity, and/or acceleration to
see the graphs created. Make values larger, smaller, positive, negative, etc.
When you feel like you understand the simulation, move on to the next page.
The Moving Man computer simulation, p. 2
Motion Simulation: The Moving Man
Thanks to Tom Reeve, Lincoln High School for submitting this activity to the pHET website.
Constant Velocity
1. Reset all of the man's values to zero.
2. Using the position slider, set the man to stand near the tree. Give him a velocity of 1.2 m/s (and an
acceleration of 0).
3. Click  to start the man in motion until he hits the wall, then hit to stop recording.
4. Use the playback feature to answer these questions.
a. What happened to the blue position slider
as the man moved across the screen?
b. What happened to the red velocity slider
as the man moved across the screen?
5. Use the playback feature to record the man's position
and velocity data.
5. Plot your data in the graphs below:
The Moving Man computer simulation, p. 3
6. According to your graphs...
a. What shape is your position graph?
b. What is the slope of your position graph?
c. Why does or doesn't your answer to b. make sense?
d. What shape is your velocity graph? Is it horizontal, vertical, or diagonal?
e. Why does or doesn't your answer to d. make sense?
Constant Positive Acceleration
1. Reset all of the man's values to zero.
2. Using the position slider, set the man to stand near the tree. Give him a velocity of 0 m/s and an acceleration
of 0.5 m/s2.
3. Click  to start the man in motion until he hits the wall, then hit to stop recording.
4. Use the playback feature to answer these questions.
a. What happened to the blue position
slider as the man moved across the
screen?
b. What happened to the red velocity
slider as the man moved across the
screen?
5. Use the playback feature to record the man's
position and velocity data.
6. Plot your data in the graphs below:
The Moving Man computer simulation, p. 4
7. According to your graphs...
a. What shape is your position graph?
b. Why does or doesn't your answer to a. make sense?
c. What shape is your velocity graph?
d. Why does or doesn't your answer to c. make sense?
e. What is the slope of your velocity graph?
f.
What does the slope of the velocity graph represent?
Constant Negative Acceleration
Set up a scenerio where the moving man starts quickly at the left brick wall (-10 m) but slows
done to a stop (negative acceleration) AS CLOSE TO the right brick wall (+10 m) as you can
make it .
Figure out what the initial velocity and acceleration numbers should be to stop as close to the
right brick wall as you can. Write these two numbers down on the next page.
The Moving Man computer simulation, p. 5
Your velocity (initial): ________________________________________ m/s
Your acceleration: ______________________________________ m/s/s
8. According to your graphs...
a. What shape is your position graph?
b. Why does or doesn't your answer to a. make sense?
c. What shape is your velocity graph?
d. Why does or doesn't your answer to c. make sense?
e. What is the slope of your velocity graph?
f.
What does the slope of the velocity graph represent?
Making Connections
1. What happens to the man when he is accelerating?
2. What is the difference between an object with constant acceleration and an object with constant speed?
3. Complete the following sentences:
a. "The slope of a linear position graph tells us the _________________________ of the object."
b. "The slope of a linear velocity graph tells us the _________________________ of the object."
c. "For an object moving at a constant speed, we would expect to see a position graph with a
___________________ shape and a velocity graph with a ___________________ shape."
d. "For an object moving at a constant acceleration, we would expect to see a position graph with a
___________________ shape and a velocity graph with a ___________________ shape."
The Moving Man computer simulation, p. 6