Professor Shihabi, Page 1 of 6
Physical Science Exp#3: Motion
NOTE: This is the procedure part of the experiment and it is a protected document. To submit
experiment#3 for grading, you must take the Lab assessment (Lab quiz). Check the instructions
in the pertinent lab folder. Note that the questions below are in the multiple-choice format in the
Lab Quiz.
Objectives:
1. Given values of velocity and acceleration, describe the motion of an object in detail.
2. Solve problems that involve positions, time and velocity.
3. Given values of velocity and acceleration, describe the graph of position versus time of an
object in detail.
4. Given only the graphs of position versus time of several accelerated objects, sort the objects
based on their acceleration.
Part 1: Pre-lab Preparation:
1)
Watch my video over acceleration
https://www.youtube.com/watch?v=6g6bm9H3KE0&feature=youtu.be (press “CTRL”
then click on the link). Pay special attention to minute 8:40 where the concepts in this lab
are explored.
2) Examine the interactive animations at: http://www.fearofphysics.com/Xva/xva.html. You
may set the initial speed and the acceleration of two different vehicles at various values
then observe their motion. This should prepare you for the simulation in this lab.
3) Playing the simulation: you are ready to start this lab. Go to “The Moving Man” simulation
at https://phet.colorado.edu/en/simulation/moving-man. The simulation is java-based, to
learn how to activate java for this simulation watch this video:
https://youtu.be/ikJdirUPOeE
If you are still having trouble activating java, I found this openstax link as an alternative:
https://archive.cnx.org/specials/e2ca52af-8c6b-450e-ac2f-9300b38e8739/moving-man/
4) In the activity below, you will be given set of values for the position, initial velocity, and
acceleration.
FIRST, you will predict the motion. SECOND you will input the given values into the
simulation and test your predictions. FINALLY, you will record your observations by
describing the motion (using the physics terminology in your description).
Part 2: Describing the motion ACTIVITY:
(a) Predict the motion of the man based on the conditions stated below in the table and state the
rationale behind your prediction. Here are some physics-related terminologies needed in your
description: “starts”, “ends”, “at rest”, “constant speed”, “to the right”, “to the left”, “comes to a
stop”, “slows down” (decelerates), “speeds up” (accelerates),
Set the conditions per the table below and play the simulation pertinent to each condition.
Important: (a) Click on the “Reset All” tab after you finish each simulation to reset it for the
next one. (b) Stop the simulation as soon as the man hits the wall.
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Describe (using complete sentences) the motion of the man pertinent to the conditions in the
table. Observe and describe the motion (before he hits the wall for all cases).
Reflect upon your prediction and try to figure out where you went wrong.
NOTE that + and – refer to the direction of the vector quantities. They are not part of the
magnitude (quantity’s value and unit), where“ + ” means “toward the right”, while “ - ” means
“toward the left”.
Position Initial Acceleration Prediction
(m)
Velocity
(Use Blue font)
(m/s)
(m/s2)
- 9.0
+2.5
0.0
0.0
+1.5
- 0.1
Description
(Use green font)
The predictions will NOT
(This is question 1 in the Lab
be part of the lab Quiz. It is quiz)
important, however, to
implement what you
learned in the lecture part
prior to playing the
simulation.
(This is question 2 in the Lab
quiz)
(This is question 3 in the Lab
quiz)
- 10.0
+5.0
+0.5
(This is question 4 in the Lab
quiz)
8.0
0.0
-1.0
(This is question 5 in the Lab
quiz)
0
- 2.0
-1.50
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(This is question 6 in the Lab
quiz)
0
-4.0
+.5
A) Questions (answer the questions in complete sentences):
7) (This is question 7 in the Lab quiz)
When the acceleration is zero, what can you say about the velocity of an object?
8) (This is question 8 in the Lab quiz)
Is it possible to have negative velocity but positive acceleration? If so, what would this mean?
(Hint: Check the sixth condition in the table above)
9) (This is question 9 in the Lab quiz)
Can the acceleration be negative, yet the object is accelerating (speeding up)? If so, what does
this mean? (Check the fifth condition)
B) Fill in the blank (you may play with the simulation to test the accuracy of your answers):
10) (This is question 10 in the Lab quiz): If the man is moving from a position of 0 m to 6.00 m
in 3.00 seconds he will move __________ if he moved from a position of – 4.00 m to 0 m in 3
seconds. Answer choices: [slower than, faster than, at the same speed as]
11) (This is question 11 in the Lab quiz): Looking at the position of the house and the tree, if
the man ran starting from the house going to the tree in 8 seconds, the average velocity would
be ______________.
Explain (you may use math or verbal explanation):
12) (This is question 12 in the Lab quiz): Starting at a position of 0 m, if the man is moving at a
constant velocity of +2 m/s, it will take him ____________ seconds to reach a position of 12 m.
Part 3: Describing motion from position vs time graph:
Background information:
As we learned in experiment#1 over Graphs:
The slope of a curve is defined as the change in the y or vertical values divided by the change in
the x or horizontal values. This can be stated in symbol notation as y/x. Read this as “delta y
over delta x” ( means “change in”). Using, s as the symbol for the slope we can write
Professor Shihabi, Page 4 of 6
slope  s 
y y
change in y
 2 1
change in x x2  x1
(General equation)
Hence:
1) if the slope is the same throughout the curve (Slope = positive constant), then the graph will
yield a straight-line graph with a positive slope. This represents graph b in Figure 1.
2) If the slope is increasing throughout the curve, it will yield a curve concaved up (parabola).
This represents graph “a” in Figure 1.
3) If the slope is decreasing throughout the curve, it will yield a curve concaved down. This
represents graph “c” in Figure 1.
4) if the slope is the same throughout the curve but negative (Slope = negative constant), then
the graph will yield a straight line with negative slope. This represents graph d in Figure 1.
y
Figure 1
x
Now if we look at the graph of position versus time (Figure 2) . Here we replaced y-axis with
“position” and the x-axis with “time”
Figure 2 : position vs time graph
What is the equation of the slope of position versus time graph in Figure 2?
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Since slope  s 
y y
change in y
 2 1
Therefore,
change in x x2  x1
slope  s 
change in position
change in time
We learned that distance is equal to the change in position. Hence, the slope of the position vs
time graph is the velocity.
slope  velocity 
change in position
dis tan ce

change in time
time taken
Therefore, 1) graph “a” in figure 2 indicates accelerated motion (parabola)
2) graph “b” in figure 2 indicates constant velocity in the positive direction (straight line with
positive slope)
3) graph “c” in figure 2 indicates deceleration (curve concaved down)
4) graph “d” in figure 2 indicates constant velocity in the negative direction (straight line with
negative slope)
Graphs’ Activity:
Predict the shape of the curve of the “position vs time” graph for the motion of a man based on
the conditions stated below in the table. Is it like graph a, b, c, or d in figure 2, page 4.
State the rationale behind your prediction?
Here are some phrases that you are expected to use while describing a graph: “straight line with
a positive slope”, “curve concaved up or parabola”, “curve concaved down”, or “straight line
with negative slope”.
Switch to the “chart” menu in “The Moving Man” simulation by clicking on the “charts” tab.
Set the conditions per the table below and play the simulation pertinent to each condition
Important: (a) Click on the “Reset All” tab after you finish each simulation to reset it for the
next one. (b) Stop the simulation as soon as the man hits the wall.
Record the type of “position vs time” graph obtained (ignore the other two graphs of velocity
and acceleration vs time). Is it like graph a, b, c, or d in figure 2, page 4.
Reflects upon your prediction and try to figure out where you went wrong.
NOTE that + and – refer to the direction of the vector quantities. They are not part of the
magnitude (quantity’s value and unit), where“ + ” means “toward the right”, while “ - ” means
“toward the left”.
We have the following conditions:
Position Initial Acceleration
(m)
Velocity
(m/s2)
(m/s)
Graph Prediction
Description of Graph
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0.0
+2.0
0.0
0.0
+4.5
- 1.0
The predictions will NOT be
(This is question 13 in the
part of the lab Quiz. It is
Lab quiz)
important, however, to
implement what you learned in
the lecture part prior to playing
the simulation.
(This is question 14 in the
Lab quiz)
(This is question 15 in the
Lab quiz)
10
-4.0
0
(This is question 16 in the
Lab quiz)
0
0
+5.0
Question:
17. (This is question 17 in the Lab quiz): We have established that a parabola represents
acceleration. Which one of the two parabolas below (A) or (B) represent bigger acceleration?
Why?
position
position
time
(A)
time
(B)