Copy of Lab-1 Report
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School
Temple University *
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Course
1061
Subject
Aerospace Engineering
Date
Apr 3, 2024
Type
Pages
5
Uploaded by BaronMoonDeer7
Lab 1 Motion in 1 Dimension
Goals:
-
The purpose of this lab is to demonstrate/explore some real world applications of motion,
specifically acceleration, velocity, and time using the photogate sensor. Moreover, this lab
helps to familiarize us with the Capstone and Excel applications.
Procedure:
-
In part 1, we dropped a flagged ruler through the photogate sensor to record the time
between each flag. The data was placed into a table which recorded time (seconds),
position (m), and velocity(m/s). This procedure was repeated by 6 teams which was
documented in excel. Some discrepancies that were found between tests were that
depending on the drop height of the ruler the position and times recorded varied and in
some cases did not exist.
Error and precautions:
-
An error that could have occurred was the picket fence not clearly going through the
photogate. The measurements would have been off or if the red light on the back of the
stand never went off that would mean no data was collected and the run would have to be
restarted.
-
Another error would be conversions and putting in incorrect flag spacing measurements.
The computer would collect incorrect values for the picket fence position, which would
affect the measured velocity.
Results:
Trial
Acceleration
m/s
1
4.8418
2
0.0929
3
0.1171
4
0.0966
5
0.2425
6
0.0841
avg
0.9125
stand dev
1.75805969
Questions:
Question 1
. Looking at the data, you should notice that the time difference between successive
data points is smaller and smaller the farther the picket fence falls. Why is this?
-
The difference between the successive points getting smaller and smaller is the result of
acceleration. The photogate sensor is recording the times between the subsequent lines on
the ruler. As the ruler accelerates and gains velocity or overall displacement, naturally the
times between the next dash will shorten.
Question 2
. How does the computer know the velocity when all it is measuring is time? Hint:
what is the other part of the equation for average velocity?
-
The other part of the equation for average velocity is displacement, so the computer
knows the velocity when measuring time because the photogate is also recording the
position of the picket fence and the flag spacing is recorded as well to give accurate
results when the the black strips on the picket fence are blocking the red beam.
Question 3
. If we want the slope to be the acceleration, which variable, velocity or time, goes on
the x-axis? Why?
-
If we want the slope to measure acceleration then we would need to measure the x-axis
using time. This is because the slope is measured as rise over run or y/x and if we want to
measure acceleration which is velocity/time; Thus, time would have to be in the
denominator.
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Question 4.
Describe in words the shape of the velocity vs. time graph. (Does the slope stay
constant? Is the y-intercept zero?)
-
The difference between velocity and a time graph, is the difference between a graph f(x)
and f’(x). Unlike time, velocity measures direction, or rather, factors it in. In the case
where you sometimes drive a total 3 hours and 300 miles from Philadelphia to Pittsburge,
a time graph would express just that, you traveled 300 miles in 3 hours moving a x mpx.
However, a velocity graph would indicate that your overall displacement is zero because
you started and ended at the same location.
Question 5
. Describe in words the shape of the distance vs. time graph for the free fall. How
should this look (linear, quadratic, etc.)?
-
The shape of the distance vs. time graph is linear and starts at (0,0) and gradually
increases on both the x-axis and y-axis, making it go diagonal.
Question 6
. Look at your list of 6 slope values (i.e. acceleration values) and, in one or two
qualitative sentences, report how reproducible your acceleration results appear (e.g. very similar
values, widely varying from one trial to the next, etc.).
-
Our values for most of the trials were similar. However, runs one and five seemed to be
outliers compared to the rest of the data. I think that some of our data would be
reproducible, considering the similarity of the numbers, but I do not believe our results
are reproducible overall.
Question 7
. Is your standard deviation low when compared to the value of your average? As a
rough guideline, a standard deviation less than 10% of your average is OK (but the lower the
better!). Does this standard deviation seem reasonable with what you put for your quantitative
description of reproducibility in Question 6? This shows how standard deviation is a measure of
reproducibility.
-
Our standard deviation was higher than our acceleration values. As mentioned above, we
believe that the data is not reproducible, and the standard deviation being higher than the
average acceleration instead of lower supports that idea.
Question 8
. Looking at this equation, what would the standard deviation be if all of your
measured values were the same? Explain.
-
The standard deviation would be close to 0. Looking at the data, it can be seen that the
first run is the outlier in regards to acceleration. This caused our standard deviation to be
higher than the average. So, if the values were all the same, the standard deviation would
be close to or zero.
Discussion:
The final result of this lab did not result in us getting the expected value of 9.8 m/s
2
, ending up
with 0.9125m/s
2
. This is likely due to significant measurement errors. As outlined in our
error
and precautions
this lab was prone to a great deal of deviation from the desired outcome as a
result of human and equipment error. There were two primary errors that we suspect contributed
to the discrepancies in our data. This first, which almost certainly happened and is supported by
the presence of a standard deviation in the first place, is that the photogate sensor is inaccurate to
some degree. The second discrepancy we suspect occurred during the execution phase of this
project. While recording that data we record the data in cm instead of meters and convert the
units twice. This would make sense given that our final result was 0.9125m/s
2
which is off by a
degree of 100. If this hypothesis is accurate, it would make our final result 9.1m/s
2
which is much
closer to the expected value of 9.8 m/s
2
.