Copy of Lab 7 Concussions
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School
Temple University *
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Course
1061
Subject
Aerospace Engineering
Date
Apr 3, 2024
Type
docx
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5
Uploaded by BaronMoonDeer7
Lab 7 Concussions
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Goals
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The goal of this experiment is to experiment with physical analysis of collisions with real-
life problems and compare the impulse from the collision data with and without a helmet.
Procedure
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For part I, we set up the force sensor at the end of the elevated track and took the helmet off the head attached to the force sensor. We started the cart at 40 cm, released it, recorded the data with a force vs. time graph, and found the impulse with the graph. We did three trials of this. We did three more trials of this with the helmet on. Error and Precautions
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Possible error is not zeroing the force sensor, causing incorrect data to occur. -
Another possible error is the angle of the track, or the track being elevated too high. Results
Impulse (N*s)
F
max
(N)
Δt (s)
Without helmet Trial 1
-0.13678
-18.14173
2.685
Trial 2
-0.13705
-17.27095
2.268
Trial 3
-0.13543
-16.85058
2.663
Average
-0.13642
-17.42109
2.539
With helmet Trial 1
-0.11757
-10.18466
4.108
Trial 2
-0.12141
-11.14552
4.467
Trial 3
-0.12232
-11.50584
3.033
Average
-0.120433
-10.94534
3.86933
WITHOUT HELMET
WITH HELMET
Questions
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Question 1. What quantity is represented by the area under the curve in a graph of force vs.
time?
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Impulse is represented by the area under the curve in a graph of force vs. time.
Question 2.
How does the duration (i.e., the time scale) of the impact differ between the two
cases (with vs without the helmet)?
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The duration differs because the average time is nearly twice as long with a helmet than
it is without a helmet. Question 3.
Compare the average impulse from the trials with the helmet to those without the
helmet. Was there a significant difference (more than about 20 %) in the average impulse
between the two conditions? Was there a significant difference in the average maximum force
between the two? It has been shown that higher accelerations of the head cause concussions,
does your data support the common assertion that helmets help prevent concussions? Support
your answer.
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The average impulse with and without the helmet were -0.12043 N*s and -0.13642 N*s,
respectively. The percent difference between the two situations was 12.45%, meaning
that there was not a significant difference in the average impulse. There was a 45.67%
difference in the average maximum force. Our data confirms that higher accelerations of
the head increases the chance of concussion because the impulse of the trials without
the helmet were greater, increasing the chances of getting a concussion.
Question 4.
When the person experiences a rotational acceleration of 7000 rad/s2. what value
of linear acceleration in g’s would result in a 5 % chance of concussion? What linear
acceleration causes a 5% chance of concussion when the rotational value is lowered slightly to
6000 rad/s2?
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If rotational acceleration is 7000 rad/s2, 30gs of linear acceleration would produce a 5%
chance of a concussion. If there is a 5% chance of getting a concussion when the
rotational acceleration is 6000 rad/s2, then the linear acceleration must be 50gs.
Question 5.
Calculate the linear acceleration of the cart from Part I using the trial with the
highest force value you recorded. To do this, assume the cart has a mass of 0.2 kg and use
Newton’s 2nd Law to find the acceleration. Then Using this value of linear acceleration in g’s
refer to Figure 1 to determine the rotational acceleration that would have to occur for a 1%
chance of concussion in your experiment.
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Using the first trial, the maximum value value of force was -18.142 N. Assuming the
mass of the cart is 0.2 kg, we can use the second law of motion (F=m*a) to solve for
acceleration, which is -90.71 m/s2. Taking the absolute value of the acceleration and
using Figure 1, a rotational acceleration value of 2000 rad/s2 would have to occur for a
1% chance of a concussion.
Question 6.
The CDF is the fraction of observations that are below the specified value on the x-
axis. For example, about 90 percent of the sub-concussive impacts in the HITS data (solid black
line) occurred at accelerations below 50 g. According to the NFL data set, what was the highest
acceleration experienced that did not cause a concussion? What was the minimum acceleration
that did cause a concussion?
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The highest linear acceleration experienced that did not cause a concussion was 100gs.
The minimum linear acceleration that did cause a concussion was 30gs.
Discussion
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In conclusion, from our data you can see that wearing a helmet decreases the chances of getting a concussion from collision compared to not wearing a helmet, but not too significantly. The difference in impulse was a 12% decrease with a helmet compared to
without a helmet and the maximum force was a 45% decrease with a helmet compared to without a helmet.