Constant Velocity Lab (Buggy Cars):
Experiment No. 2
Submitted By:
Sebastian De La Pena-Kenley
Period 3: STEM AP Physics 1
September 20, 2019
Constant Velocity Lab (Buggy Cars)
Experiment No. 2
I. Objective: To examine the motion of the buggy, in regards to its velocity (the position of the
buggy with respect to time)
II. Hypothesis: (Write your prediction about the outcome of this experiment.)
The more spaghetti strands, the more weight that can be supported.
III. Materials: (List the materials used in the experiment.)
•
•
•
•
Dune Buggy
Meter Stick
Stopwatch
Tape (marking Device
IV. Laboratory Set-up: (Take a picture or draw your lab set-up. The caption should
describe the set-up)
The car moves with a constant velocity in a straight line. We mark its position every 2 seconds
with a piece of tape.
V. Procedures: (Write the step-by-step procedures of your experiment using your own
words. Guideline: Write your procedures in a way that can be followed easily by anyone
who would like to repeat your experiment.)
Part 1
a) 1. Set the buggy car to a slow speed using the dial.
b) 2. Mark the starting point on the floor using a piece of masking tape. (This is the
0 cm point.) When you begin, the front of the car should be at the starting point.
c) As the timer reads the time aloud (every 2 seconds) the marker should mark the
position of the front of the car with a small piece of masking tape. Take 10 data
points.
d) Measure the displacement of all the marks from the starting point and record the
data in data table 1 and repeat.
Part 2
a)
b)
c)
d)
Set the buggy car to a fast speed using the dial.
Remove the tape marks from part
Repeat steps 2-3 from part 1.
Measure the displacement of all the marks from the starting point and record the
data in data table 2 and repeat.
Part 3
a) Remove the tape from part 2.
b) You may do TWO of the following with the faster car
a. Car starting from a positive position going to the negative position and NOT
crossing the origin
b. Car starting from a positive position going to the negative position and crossing
the origin
c. Car starting from a negative position going to the positive position and NOT
crossing the origin
d. Car starting from a negative going to the positive position and crossing the origin
e. A car going from the negative position further going in the negative position
c) Record your data in table 3 and repeat.
VI. Data
TABLE 1 (Slow Speed)
Time (s)
0
2
4
6
8
Position
0
80
145
201
268
10
12
14
16
18
20
333
385
451
510
570
631
TABLE 2 (Fast Speed)
Time (s)
0
2
4
6
8
10
12
14
16
18
20
Position
0
110
193
285
370
446
531
604
691
781
887
TABLE 3 (Positive to Negative, Crossing Origin)
Time (s)
Position
0
80
2
6
4
-70
6
-141
8
-206
10
-275
12
-348
14
-436
16
-506
18
-571
20
-637
TABLE 4 (Negative to Positive, Crossing Origin)
Time (s)
0
2
4
6
8
10
Position
-100
-41
20
88
149
220
12
14
16
18
20
292
378
463
544
625
VII. Analysis:
A. Variables: Identify your control variables, independent variable and dependent
variables in paragraph form.
The control variables in our experiment are things that are kept constant, including: the origin,
the method of placing the tape, and the method of measuring the distance between marks. The
independent variable in our experiment is the variable that does not rely on any other variable. In
this experiment, it is the position of the buggy car. The dependent variable in our experiment is
the variable that is reliant on the independent variable. In this experiment, it is time (measured in
seconds).
B. Graphs: (Graph your data table using Logger Pro, plot your points, draw your
line of best fit, determine the equation of the line)
TABLE 1: Position (cm) vs. Time (s)
700
y = 32.074x
600
Position (cm)
500
400
300
200
100
0
0
5
10
15
20
25
20
25
Time (s)
TABLE 2: Position (cm) vs. Time (s)
1000
900
y = 44.029x
800
Position (cm)
700
600
500
400
300
200
100
0
0
5
10
15
Time (s)
TABLE 3: Position (cm) vs. Time (s)
200
100
0
0
5
10
15
20
25
20
25
Position (cm)
-100
-200
-300
-400
-500
-600
y = -36.059x + 78.409
-700
Time (s)
TABLE 4: Position (cm) vs. Time (s)
700
y = 36.441x - 124.59
600
500
Position (cm)
400
300
200
100
0
0
5
10
15
-100
-200
Time (s)
C. Mathematical model (equation of the line): Explain what your equation means.
Explain the physical meaning or significance of the slope and the y-intercept.
• The slope of the equation refers to the average change in position of the dune buggy every
second.
• The y-intercept is the position in which the car begins at 0 seconds
• The f(x) is the position of the dune buggy, displayed as a function between the slope and the
current time, added by the starting position of the buggy
D. Errors: (Explain what kind of errors and sources of these errors in your lab
experiment.)
The method of placing the tape markers could be delayed, and therefore not completely
accurate.
The process of measuring the marks between pieces of tape could not be completely kept
constant, because there was no center point on the piece of tape that we could measure from
VIII: Conclusion:
In the constant velocity lab, the purpose was to examine the motion of the buggy, in
regards to its velocity (the position of the buggy with respect to time). To begin, we measured
the positions of two differently-speeded buggy’s (parts 1 and 2). In the third part, we started the
buggy at different places in relation to the origin. For the three parts, the numbers that
demonstrated position got larger as the time progressed when the buggy was moving further
away from the origin, in either direction. A constant speed graph looks like a single line, with
one slope, indicating that the car never speeds up nor slows down.
IX: Questions
Refer to your graphs from part 1 and 2 to answer the following questions.
a) Do your data points fall in a somewhat-straight line?
a. YES
b) What physical quantity is represented by the slope of the line?
a. The slope of the equation refers to the average change in position of the dune
buggy every second.
c) How does the slope of graph 1 and graph 2 compare? What does that really mean?
a. The slope for graph 2 is greater than that of graph 1. This means that for every 1
second, the buggy in graph 2 is moving further.
d) How would you recognize a graph of an object traveling at a constant velocity?
a. I could recognize a graph of an object traveling at a constant velocity because the
slope would not change from point to point.
Refer to your graph from part 3 to answer the following questions.
a) What do you notice about the shape of your graph? (Is it similar to graphs 1 and 2, or
different? Explain.)
a. The graphs remain linear. The difference between the part 3 graphs is that they
have a negative slope, because as time progresses, they go into the negative
position.
b) How does the slope of the line in graph 3 compare to the slopes of graphs 1 and 2? What
does that tell you about the motion of the car?
a. The slope in graph 3 is negative, meaning that as time progresses, the car moves
in the negative position
c) Is the velocity of the car constant or not constant? ___________________ How do you
know?
a. The velocity of the car is constant. I know this because the car is not speeding up
nor slowing down.
The Guiding Question: How does the velocity of the car
affect its position with respect to time?
Our Claim:
A car with a higher velocity will reach a further position
than the slower car in the same time frame, no matter the
origin.
Our Evidence:
Justification:
Our evidence is based on the assumption
that both cars maintain a constant velocity
and travel the distance in a straight line.
We tested in a negative position in a
positive velocity, and a positive position
with a negative velocity. With this, the car
with the higher velocity traveled more
distance that the slower car within the
same time frame no matter the initial
position.
Position (cm)
TABLE 1: Position (cm)
vs. Time (s)
800
600
400
200
0
y = 32.074x
0
10
20
30
Time (s)
Position (cm)
TABLE 2: Position (cm)
vs. Time (s)
1000
y = 44.029x
500
0
0
10
20
30
Time (s)
TABLE 3: Position (cm) vs. Time (s)
Position (cm)
200
0
-200
0
5
10
15
-400
-600
-800
y = -36.059x + 78.409
Time (s)
20
25
TABLE 4: Position (cm) vs. Time (s)
800
Position (cm)
600
y = 36.441x - 124.59
400
200
0
0
-200
5
10
15
Time (s)
20
25