Lab 08
pdf
keyboard_arrow_up
School
Pensacola Christian College *
*We aren’t endorsed by this school
Course
101
Subject
Aerospace Engineering
Date
Dec 6, 2023
Type
Pages
6
Uploaded by allisonkayee
Lab 8: Static, Kinetic, and Rolling Friction on Horizontal Surfaces Laboratory Report Name: Allison Bischoff Lab Partner(s): Karyn Fuller Jacob Varani Purpose of Experiment Write a fully developed paragraph
that describes the purpose of the experiment. Include each of the following topics: 1) the main concept(s) being investigated, 2) the variables (quantities) being measured, 3) the instruments and techniques used, and 4) the type of analysis used to draw conclusions from the data. The purpose of this experiment was for the student to observe the effects of static, kinetic, and rolling friction and to determine the effect of static and kinetic friction on types of surfaces. Because friction equals the coefficient of friction and the normal force, all of these values were found in this experiment. Since this experiment only involved a horizontal surface, the normal force and weight are equal to each other, and therefore, the weight of the object was used as the normal force. Friction was determined using a chassis with a force and acceleration sensor inside and added mass as the normal force on top connected to a hanging mass using a pulley system. The setup was tested on four different surfaces to see the effects of static and kinetic friction. After friction and the normal force were found, the equation for friction was used to calculate the coefficient of friction. After all the necessary data was collected, graphical analysis was used to compare the data. Data & Analysis Data Table 8.1 Set-Up n
(N)
Surface Trial T
s
(N)
μ
s T
k
(N)
μ
k
1 .411 Cardboard 1 .58 1.41 .53 1.29 2 .98 2.39 .62 1.51 3 .50 1.22 .55 1.34 Cork 1 1.00 2.44 .67 1.63 2 .89 2.17 .88 2.15 3 .99 2.41 .71 1.73 Rubber 1 1.66 4.04 1.12 2.73 2 1.68 4.09 1.65 4.01 3 1.46 3.55 1.43 3.48 Sandpaper 1 2.47 6.01 1.94 4.72 2 2.15 5.23 1.97 4.79 3 2.94 7.15 1.95 4.75
Lab 8: Static, Kinetic, and Rolling Friction on Horizontal Surfaces Laboratory Report Set-Up n
(N)
Surface Trial T
s
(N)
μ
s T
k
(N)
μ
k
2 .410 Cardboard 1 .51 1.24 .49 1.20 2 .50 1.22 .48 1.17 3 .40 .976 .42 1.02 Cork 1 .90 2.19 .85 2.07 2 .78 1.90 .78 1.90 3 .88 2.15 .84 2.05 Rubber 1 .70 1.71 .62 1.51 2 .87 2.12 .87 2.12 3 .72 1.76 .71 1.73 Sandpaper 1 2.31 2.31 2.30 5.61 2 3.25 3.25 3.02 7.37 3 2.40 2.40 2.37 5.78 Data Table 8.2 Averages and Percent Errors for Static and Kinetic Friction Surface
Avg. T
s
Avg. μ
s
μ
s
% Error Avg. T
k Avg. μ
k
μ
k
% Error Cardboard .58 1.41 189% .46 1.13 207% Cork .91 2.21 277% .82 2.01 335% Rubber 1.18 2.88 330% .73 1.79 229% Sandpaper 2.59 4.39 450% 2.56 6.25 923% Data Analysis Question: Which surface had the higher average static and kinetic tension. Why is this the case? Support your answer with your data.
Sandpaper had the higher average friction for both static and kinetic tension because it has a rough surface.
Lab 8: Static, Kinetic, and Rolling Friction on Horizontal Surfaces Laboratory Report Data Table 8.3 Set-Up n
(N)
Surface Trial T
r
(N)
μ
r μ
r
% Error 3 .410 Cardboard 1 .16 .390 86% 2 .17 .414 97% 3 .16 .390 86% Cork 1 .26 .634 99% 2 .26 .634 99% 3 .26 .634 99% Rubber 1 .26 .634 171% 2 .27 .659 182% 3 .25 .610 161% Sandpaper 1 .25 .610 155% 2 .26 .634 165% 3 .25 .610 155% Data Table 8.4 Averages and Percent Errors for Rolling Friction Surface
Avg. T
r Avg. μ
r
μ
r
% Error Cardboard .163 .398 90% Cork .26 .634 99% Rubber .26 .634 171% Sandpaper .253 .618 158% Data Analysis Question: Which surface had the higher average rolling tension. Why is this the case? Support your answer with your data.
Sandpaper had the highest rolling tension because of its rough surface.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Lab 8: Static, Kinetic, and Rolling Friction on Horizontal Surfaces Laboratory Report Graphs 0.46
0.82
0.73
2.56
y = 0.4102x - 0.0041
R² = 1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
-2
0
2
4
6
8
average tension (T)
average μ
average μ and tension for kinetic friction
average μ and tension for kinetic friction
Linear (average μ and tension for kinetic friction)
Lab 8: Static, Kinetic, and Rolling Friction on Horizontal Surfaces Laboratory Report Post-lab Questions 1.
At what inclination would a system experience the greatest force from friction? At what inclination would the system experience the least? Explain both of your answers. The greatest force from friction would occur when theta is equal to zero, and it would experience the least force from friction when theta is equal to 90. This is because the cosine of 90 is 0 which would make the force from friction zero, and the cosine of 0 is one which would make the force from friction equal to the coefficient of friction times the mass and gravity. 2.
How does the total mass of a sliding object affect the force of friction on the object? Mass and friction are directly proportional so if the mass increases so will the friction 3.
According to your data, how does changing the surface material change the tension required to move the sliding weight? The greater the coefficient of friction the greater the tension
4. What other items should we consider when we are looking for all the forces of friction in a system? (HINT: Think about the setups in this lab.) The weight of the hanging mass and the friction of the pulley and string 5. Explain in your own words what is the tension required to move the block on a flat surface. In order to move a block on a flat surface, the force of tension must be greater than the force of friction on the object. Error Analysis Write a fully developed paragraph
discussing at least three
errors that occurred during the laboratory experiment. For each error discuss the following: what was
the error, what caused
the error, and how did the error affect
the recorded/calculated data value(s)? Report percent error or percent discrepancy as applicable. The first source of error occurred while adding hanging mass to overcome the force of friction in which the object accelerated abruptly instead of moving at a slow constant velocity. This error was caused by not being able to add smaller increments of weight at a time. That data was affected in that the kinetic friction was sometimes greater than the static friction. However, kinetic friction should always be less than static friction because it takes more force to overcome friction when the object is at rest than it does to keep the object moving. This error caused the percent error to be significantly higher and gave values that are difficult to be compared.
Lab 8: Static, Kinetic, and Rolling Friction on Horizontal Surfaces Laboratory Report The second source of error is the lack of consideration of the friction from the pulley and the string. In order for the experiment to be executed correctly, the string had to be parallel to the tabletop. However, because the levelness of the pulley had to be measured with the human eye, there is a chance for error. If the string is higher/lower than the tabletop, then the friction would be increased/decreased. The percent error for every trial was extremely high, and this error could be a contributing factor. The third source of error occurred while collecting the data for kinetic friction in that there were no “
little squiggles
”
after the highest point on the graph. This error may have been caused by the chassis accelerating instead of moving at a constant velocity. Because the graph did not represent how it was described in class, the inaccuracy of the values for kinetic friction may have been caused by this error. Again, the percent error for every kinetic friction value was very high which could have been caused by multiple things, and this error could be one of them. Conclusions
Write a fully developed paragraph
. State whether your execution of the procedures was a success
or failure based upon your purpose section. Support your conclusion(s) by providing relationships, trends, or specific numerical examples from your data. My conclusion from this lab was that it was a failure. In this experiment I expected to observe the effects of static, kinetic, and rolling friction and to determine the effect of static and kinetic friction on types of surfaces. However, since the percent error for each trial was significantly high (> 100%) and the relationship between kinetic and static friction was inaccurate, the values cannot be compared for an accurate representation of their relationship. Overall, it was difficult to determine the effects of each surface because the values were so inaccurate, and for these reasons, I would consider this lab to be a failure.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help