Lab deck: Multiple
Johann Alcaraz
Mary Regacho
Mariah Barrera
Lab #39: Angular Position vs. Velocity
Purpose
Apparti
Theory
Methods
Analysis
Analysis
Conclusions
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To use the Datastudio program to record data and analyze data
To plot angular position and velocity
To use the rotary motion sensor to measure the rotation of a disk that undergoes
constant angular acceleration .
to understand the relationship between angular and linear velocity
Mariah; assigned
Every kinematic quantity has an analogous quantity in rotational kinematics. The
rotational version of position is the "angular position". The rotational version of velocity
is "angular velocity" that.
The motion of a fan cart accelerating on a flat track is described as
translational kinematics.
Angular displacement, angular velocity, and angular acceleration can be brought together
to produce a set of equations called the equations of kinematics for constant angular
acceleration.
The equations of kinematics for constant angular acceleration can be used for solving
problems involving rotational motion..
The lab group followed this provided set of procedures as
accurately as they could with a few minor changes in that
they repeated a few of the steps. All in all, these
procedures were their guides.
Setup
1.
2.
3.
4.
5.
6.
7.
collect materials
situate group at lab deck
delegate jobs from person to person
read through lab packet as a group and formulate a plan of attack
Set up the PASCO Interface and computer and start DataStudio.
Connect the Rotary Motion Sensor to the interface.
Open the DataStudio file: 39 Rotational Motion.ds.
o
The DataStudio file has graph displays of Angular Position and Angular
Velocity versus Time. The Rotary Motion Sensor is set to record at 20 Hz.
8. Mount the Rotary Motion Sensor on a support rod.
9. Mount the Super Pulley with Table Clamp on the end of the Rotary Motion
Sensor.
10. Attach one end of a piece of thread (about 1 m) to the hole in the edge of the
medium diameter part of the three-step pulley on the Rotary Motion Sensor.
11. Adjust the Super Pulley and thread so the thread is tangent to the medium pulley.
12. Remove the thumbscrew that holds the three-step pulley onto the sensor. Place the
disk of the rotational accessory on the top of the three-step pulley and replace the
thumbscrew to hold the disk in place.
13. Attach a mass hanger to the end of the thread. Turn the disk to wind the thread
until the mass hanger is almost up to the Super Pulley.
14. Hold the disk until you are ready to record data and measure the rotational
motion.
Procedure
1. When you are ready, click ‘Start’ to begin
recording data. Release the disk so it is free to
rotate.
2. Allow the disk to rotate until the string is almost
completely unwound. Click ‘Stop’ before the string
unwinds all the way.
3. Click the ‘Scale to fit’ button to rescale the graph if
needed.
Questions
1. How does the shape of the graph of angular position versus time compare to the
graph of linear position versus time?
-Angular position vs. time is curved, but linear position vs. time is linear.
2. How does the shape of the graph of angular velocity versus time compare to the
graph of linear velocity versus time?
- the graph of angular position was a curved graph, while the graph of linear
position was linear.
3. What are possible sources of error in this activity?
- The possible sources of error in this activity are the first of all human error. We
did this lab in less than 10 minutes, so there is a high possibility that we might
have missed something as a group. Another source of error could be the
limitations of the equipment used.
4. Linear acceleration is determined by the ratio of the net force on an object to the
mass of the object. Based on this exploration, do you think there is a similar ratio
that determines the angular acceleration of a rotating object?

Yes, this ratio probably has the same concept of force over mass to get
acceleration. This relationship could probably be seen by the equation
FR=MaR=Mv2/r you would just need to manipulate the equation to get
acceleration.
JOHANN'S CONCLUSION
Results
From the data, we can conclude that the graph of angular velocity vs. time is an
apparent derivative of the angular position vs, time graph. This is seen by the type of
graph plotted with velocity being linear and position being parabolic. It is also seen that
velocity is increasing at a constant rate.
Purposes
1. To use the Datastudio program to record data and analyze data
- The recording was easily accomplished through doing the lab procedures but the
analyzation of the data did not get anywhere; Mary and I both found the analyzation
difficult and just took it as it came through our knowledge of graphs and relationships.
2. To plot angular position and velocity
- Data Studio automatically fulfilled this purpose for us.
3. To use the rotary motion sensor to measure the rotation of a disk that undergoes
constant angular acceleration
- Again, this was basically a no-brainer fulfilled by bascially just doing the lab, or in this
case, watching Raymond do the lab.
4. To understand the relationship between angular and linear velocity.
- From this lab, I really don't understand it. I did not accomplish this purpose through this
lab.
Knowledge
Frankly, these labs weren't very helpful to me. My lack of preparation surely was one
of the factors why but other reasons came into play as well. Perhaps the calss failed to
participate in Socratic dialogue agauin which reuslted in these set of labs. In my opinion,
three, four, or five labs at once isn't working very well. Even if the lab reports are due 5
days later.
I may not have much knowledge to contribute in this conclusion but I think it's
apparent that I did not comprehend much. However, what I do have to offer is an
alternative way to complete this arrangement of labs. Instead of having a variety of labs
at differnet stations, and having griups alternate bewteen lab decks. How about, each
group does the same lab at their own lab deck on the same day. That way, they dont have
to worry about getting to other labs. Each group will be able to complete the lab on the
same day, and perhaps allow for more group communication and sharing of results. As
for the lab write-ups, rather than it being all due collectively on one day, the lab would be
reasonably due 2 days later. So basically, all groups do a lab on Monday, and the write up
due Wednesday night. With this, 4 labs can be accomplished in 1 week, but in a more
orderly fashion and allow for less "stress" and more collaboration and thought process.
This may not be the cutomary conclusion, but I believe I've put in my two cents and
given what knowledge I do have of the situation. As much time as you have spent
preparing those templates for us (which I thank you), I dont think that was the best way to
minimize our time spent on the lab write-ups. To me, it just allowed more shortcuts and
therefore allowing laziness to seep in. In the process of writing up labs, typing up the
procedures as the group specifically did them, retyping the background information or
theory in our own words, and such, played a crucial role in my development of
understanding. I think that is why I did much better on the latter set of 5 labs (Newton's
Laws) compared to this.
Mary’s conclusion
Results

The data collected shows that angular velocity is the derivative
of angular position. This relates to the concept in translational motion
where the velocity of an object would be a derivative of the positional
graph. The differences between the two types of motion is that
displacement in rotational motion would be represented in angles.
Purposes

The first purpose was completed by utilizing the Datastudio
program and sensors to record the data. Using the Datastudio program
also enabled us to plot the angular position and velocity. And this also
accomplishes our third purpose of using the rotary motion sensor to
detect the constant accelerating motion. The equipment used helped us
to plot angular position and velocity.
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The fourth purpose was fulfilled when my partners and I looked
at the graphs analyzed the graphs in order to answer the questions.
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Finally, the fifth purpose of the lab was fulfilled by answering
the questions the lab gave us. The questions in the lab hinted at a
connection between rotational motion and linear motion by using the
concept of Newton’s second law and using ratios. We could relate the
two ideas together with our previous knowledge of manipulating
Newton’s second law. Then the questions kept hinting at a relationship
between the graphs of velocity and position and this went back to our
knowledge of the graphs of linear motion. How the graphs of velocity
was a derivative of position, and acceleration a derivative of velocity.
Knowledge
Trying to understand angular motion from Giancoli was a real challenge. I could
barely grasp any concepts. it was difficult coming into the lab with my limited
knowledge of circular motion. I feel the pace is really hard to keep up to. These labs
would have been a lot easier if we had a stronger back round with circular motion. After
seeing the data from the lab and answering the questions I began to get a much better
understanding of the chapter. I finally understood how, rotationally, the angle is the same
thing as the displacement in linear motion. And how all linear motion has counterparts in
rotational motion. If my partners and I had more time on the lab we would try to change
the variables with velocity, radius, and mass. It would be interesting to predict what
would happen If we were to change those variables. Conducting more trails would also
be a part of our list to do. Understanding where the fluctuations in our graph occurred
and why would be a big help to making our data much more precise and accurate. If we
had more time we would try and figure out how these fluctuations came to be.
Mariah's Conclusion
Results: The graph shows that velocity plays a key role in the derivative position.
Translational and rotational also is seen on the graph.
Purposes:Plotting the velocity and angular positions using the help of datastudio. The
rotary motion sensor was used to plot these points on our graph. The questions were the
last of the purposes but I found this the most difficult because I'm still unsure of myself.
Knowledge: This lab was a little simpler and somewhat easier to follow because
observing helps me follow things more easily. I'm still unsure of myself answering
questions because I'm still not sure of how to answer questions or even where to start. I
feel doing more labs will help this become easier for me and the help of my Johann and
Mary also lifted the difficulty level.