UNIVERSITY OF NEGROS OCCIDENTAL – RECOLETOS
#51 Lizares Avenue, Bacolod City, Negros Occidental, 6100
LABORATORY MANUAL IN
ENPHYS11G
Physics for Engineers (Calculus based)
ENPHYS11G LABORATORY ACTIVITY 6
CIRCULAR MOTION
GROUP 2
SUBMITTED BY:
Suficiencia, Bernel John B.
Bando, Aiza M.
Gale, Kyra Nicole
Jison, Gian Carlos P.
Ontanillas, Angelo
Parcon, Matthew Jeff A.
March 21, 2025
1
TABLE OF CONTENTS
LABORATORY ACTIVITY 6: CIRCULAR MOTION
Page No.
I.
INTRODUCTION
02
Objectives
02
METHODS
03
Materials
03
Procedures
04
RESULTS AND DISCUSSION
07
Guide Questions
08
IV.
CONCLUSIONS AND RECOMMENDATIONS
09
V.
REFERENCES
09
VI.
APPENDICES
10
Practice Problem
11
II.
III.
2
Laboratory Experiment 6: Circular Motion
Objectives:
After this laboratory activity, the students will be able to
1. Determine the factors influence the motion of an object that travels in a circular path at a
constant speed.
2. Determine the relationship among the factors that affect the circular motion at a constant
speed.
Introduction:
Prior study of the motion of objects has mostly included linear dynamics. When an object
moves in a curved or circular path, the object is subject to a center-seeking force called centripetal
force. This force is directly related to the object's net inward acceleration. In uniform circular
motion, the object moves with constant speed yet changing direction. Thus, its velocity is not
constant, and the acceleration is non-zero.
In this experiment, you will conduct several short investigations examining how the
object's mass influences the period of a revolution under a constant force and constant radius. You
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will also examine how changing the radius of the circular path affects the period of a revolution
while the object's mass and applied force are held constant. In the final investigation, you will vary
the applied force to determine the effect on the period of a revolution when holding the radius and
mass constant.
Apparatus and Materials:
•
Force sensor – 1 set
•
Rubber stopper – 1 pc
•
Steel Rod – 1 pc
•
Stop Watch – 1 pc
•
Triple Beam Balance – 1 pc
•
Plastic tube – 1 pc
•
Timer – 1 pc
•
Table clamp – 1 set
•
String – 1.5 m
•
Scissors – 1 pc
4
Experimental Procedure
Installation of PASCO Data Collection Application:
Capstone Application Link:
https://www.pasco.com/download/capstone/win64/8676079c/9c0fcd84e8c9fbe5
Capstone License Key:
19F5C-S10o2-4o0m0-ppip3-40qr8-ece1h
Set-up:
1. Start a new experiment on the data collection system.
2. Measure the mass of the stopper and record the value in Table 6-1.
3. Connect the force sensor to the data collection system.
4. Attach the table clamp to a table with the rod connector above the table.
5. Attach the short rod to the rod connector on the table clamp such that the rod is parallel
to the floor.
6. Attach the force sensor to the short rod such that the hook of the sensor points straight
up and then push the "zero" button on the force sensor.
7. Attach a plastic tie to the stopper through the hole in the center of the stopper.
5
8. Tie the string to the plastic tie.
9. Set the radius by measuring from the center hole of the stopper (approximately the
center of mass), mark the string from the stopper’s center of mass. Record the radius in
Table 6-1.
10. Using the radius, determine the distance the stopper travels in one revolution.
𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 = 2𝜋𝑟
11. Carefully begin rotating the mass overhead. Keep the mark on the string at the mouth
of the tube to ensure the radius remains 25 cm. (Note: Always try to keep the plane of
rotation parallel to the floor.)
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12. Record the force by highlighting the stable portion of the recorded data and determine
the average force. (Note: Force is negative since the it is pulled from the sensor, record
the absolute value.)
13. Repeat data collection, rotating the mass at radius 30cm and 50cm.
Analyze Data:
1. Calculate the time it took to complete, and revolutions. Record the value in Table 6-1 in
for the different radius
2. Calculate the total distance travelled by the mass, and record the value in Table 6-1
𝑡𝑜𝑡𝑎𝑙 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 = 𝑡𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑟𝑒𝑣. = 𝑛(2𝜋𝑟)
where n= number of revolutions
3. Calculate the velocity of the mass in 10 revolutions and record the value in Table 6-1 in
for the different radius.
𝑡𝑜𝑡𝑎𝑙 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒
𝑣=
𝑇
4. Calculate the centripetal acceleration of different radius
𝑣2
Ac = 𝑟
5. Calculate the % error for the Force and record the value in Table 6-1 in for the different
radius.
𝐹(𝑡ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙) − 𝐹(𝑎𝑐𝑡𝑢𝑎𝑙)
%𝑒𝑟𝑟𝑜𝑟 = |
| × 100%
𝐹(𝑎𝑐𝑡𝑢𝑎𝑙)
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RESULTS AND DISCUSSIONS
Table 6-1
Trial
Mass of
the
rubber
stopper
(kg)
Radius,
r
(m)
Total
Distance
Covered
(10)(2πr)
(m)
Time
(s)
Velocity
𝟏𝟎(𝟐𝝅𝒓)
𝒕𝒊𝒎𝒆
(m/s)
Acceleration,
v2/r
(m/s2)
Fc
(Theoretical)
(N)
Fc
(Actual)
(N)
%
Error
(<20%)
1
0.0156
0.2500
15.7079633
3.9300
3.9969372
63.9020285
0.996871645
1.2
16.93 %
2
0.0156
0.2500
15.7079633
3.3600
4.6749891
87.4220911
1.363784622
1.4
2.59 %
3
0.0156
0.2500
15.7079633
3.7450
4.1943827
70.3713854
1.097793613
1.3
15.55 %
Trial
Mass of
the
rubber
stopper
(kg)
Radius,
r
(m)
Total
Distance
Covered
(10)(2πr)
(m)
Time
(s)
Velocity
𝟏𝟎(𝟐𝝅𝒓)
𝒕𝒊𝒎𝒆
(m/s)
Acceleration,
v2/r
(m/s2)
Fc
(Theoretical)
(N)
Fc
(Actual)
(N)
% Error
(<20%)
1
0.0156
0.3000
18.8495559
3.1800
5.9275333
117.1188371
1.827053859
2.1
13.00 %
2
0.0156
0.3000
18.8495559
3.2670
5.7696835
110.9641581
1.731040866
1.8
3.83 %
3
0.0156
0.3000
18.8495559
4.2700
4.4144159
64.9568927
1.013327525
1.2
15.56 %
Trial
Mass of
the
rubber
stopper
(kg)
Radius,
r
(m)
Total
Distance
Covered
(10)(2πr)
(m)
Time
(s)
Velocity
𝟏𝟎(𝟐𝝅𝒓)
𝒕𝒊𝒎𝒆
(m/s)
Acceleration,
v2/r
(m/s2)
Fc
(Theoretical)
(N)
1
0.0156
0.5000
31.4159265
3.5990
8.7290710
152.3933611
2.377336433
2.7
11.95 %
2
0.0156
0.5000
31.4159265
3.5540
8.8395967
156.2769383
2.437920237
2.9
15.93 %
3
0.0156
0.5000
31.4159265
3.1200
10.0692072
202.7778682
3.163334744
3.9
18.89 %
Fc
%
(Actual) Error
(N)
(<20%)
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Guide Questions:
1. If the centripetal acceleration experienced by a mass undergoing uniform circular motion
is
𝑣2
𝑟
, calculate the centripetal acceleration experienced by the rotating mass in this
experiment for each speed. Record the results in Table 6-1.
2. Using F = mac, calculate the force exerted by the string to keep the mass in a circular
path. Record the value in Table 6-1 for different radius. This will be your theoretical
force.
3. How does the calculated force (theoretical force) compare to the measured force (actual
force)?
Our actual force is greater than the theoretical force. This is because theoretical
calculations assume ideal conditions, but in reality, small variations in mass or tension can
affect the results.
4. What factors do you think contribute to any difference between the calculated and
measured force?
This might be due to timing errors or mistakes in counting the revolutions. Our
reaction time and the way we handle the equipment might also affect the results.
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IV. CONCLUSIONS AND RECOMMENDATIONS
Conclusion:
In this experiment, we studied circular motion by measuring the force needed to
keep a stopper moving in a circular path at different radii. Our actual force values were
greater than the theoretical values, resulting in percent errors ranging from 2.59% to
18.89%. These errors could be due to timing inaccuracies, miscounting revolutions, or
slight variations in maintaining a constant radius during rotation. Despite these errors, our
data followed the expected trend, showing that as the radius increased, the force also
changed accordingly.
Recommendation:
To improve accuracy in future experiments, we should use better timing techniques,
such as a more precise stopwatch or automated system. We should also carefully count
revolutions and ensure the radius remains constant throughout the trials. Additionally,
repeating the experiment more times can help minimize errors and improve the reliability
of our results.
V. REFERENCES
Halliday, D., Resnick, R., & Walker, J. (2013). Fundamentals of Physics (10th ed.). Wiley.
Serway, R. A., & Jewett, J. W. (2018). Physics for Scientists and Engineers (10th ed.).
Cengage Learning.
Young, H. D., & Freedman, R. A. (2019). University Physics with Modern Physics (15th
ed.). Pearson.
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VI. APPENDICES (included photo documentation):
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Practice Problems
1. An automobile with a 750 kg mass goes around a corner in a circular path with a radius of
22 m at 45 km/hr. What is the acceleration experienced by the car?
2. If the moon rotates around the earth once every 28 days at a radius of 384,000 km, what is
the speed of the moon in m/s? What is acceleration the moon experiences?
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RUBRICS IN GRADING THE LABORATORY REPORT
CRITERION
DESCRIPTION
Completeness All the parts of the
of the Report report are included
and organized. All
relevant data and
calculations are
shown.
Accuracy of
Information is
Data
clear, accurate,
Utilization
and precise. Shows
complete
understanding of
experimental data,
and its analysis.
Explains
thoroughly the
clear relationship
between the
performed activity
with the theories
discussed in class
lectures and the
data gathered.
Cohesiveness Shows adequacy
of the Report of results in terms
of addressing the
experimental
objectives and of
coming up with
solid conclusions
and
recommendations.
Writing Style The report is free
and Clarity
of grammatical
of Ideas
errors and written
in a style that is
appropriate. Ideas
are clearly stated
in the report.
Citations are
included.
WEIGHT Unacceptable Poor Satisfactory Good Excellent
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