How does normal force affect the force of friction and what factors contribute to that?
IV: Normal Force
DV: Force of Friction
CV: Constant speed, same object, same surface
Prediction: As the Normal force increases, the force of friction increases proportionally.
Apparatus:
- Block with two different types of surfaces
- force meter
- different amounts of weight
- Logger pro
Procedure:
1. Attach the block with two surfaces to force meter and plug it in to the computer.
2. Pull the force meter that is connected to the block with two surfaces, horizontally.
3. Use logger pro to write down the mean amount of newtons it took to pull the block from meter.
4. Add weight gradually to see how the added weight affects the force of friction.
5. Collect data and see how it affects the force of friction
6. Convert miligrams to gramsgrams to kg by diving by 1000 then multiply by 9.8N/kg to get newtons.
7. Turn block over and use the other surface of it
8. Repeat steps 1-5
Data Collection:
VM: As the Normal Force increased (N), the Force of friction (N) increased proportionally.
MM: Force of Friction = (0. 3744 N/N) Normal Force + 0.1156 N
Slope: For every Newton of normal force, the force of friction increased 0.3744 N.
Y-int: When normal force is at 0, force of friction is at 0.1156 N
MM: Force of Friction = (0.3029 N/N) Normal Force - 0.146 N
Slope: For every Newton of normal force, the force of friction increased 0. 3029 N
Y- int: When normal force is at 0, force of friction is at -0. 146 N.
Conclusion:
We were trying to find out in this experiment, what factors went into how normal force affected the force of friction and what degree of effect took place. We found out that the increase of normal force, through the added weight on the block led to a proportional increase in force of friction. This also showed that the different surface also affects the amount of friction force is in effect. With the vinyl there was a larger force of friction than the felt because they were different surfaces used. Our variables for the experiment were the force of friction and normal force. However, the way were able to change the normal force to see how it affected force of friction was by adding different weights to the block and seeing how it affected the force of friction.very nice
The thing that was the same for everyone's graph was that everyone's force of friction grew proportionally with the added weight. What was also the same was that the vinyl force of friction was higher than the felt force of friction. What was different was the slope of everyone's graph. This may be because people tried to be as accurate as they could with the mean average of the force of friction.
but the slopes were roughly the same for everyone
Drawing Conclusions:
Two people wearing identical shoes can have different forces of friction if they have different normal forces. This is true because with a different normal force is also different weight of each person. If they have different weights, they may also have different forces of friction because as normal force increases, the force of friction also increases.
Two people who have different shoes can have the same forces of friction by the same principle. If the person has a larger weight but a smoother shoe surface that may be the same force of friction on someone with a lighter weight but with a rougher shoe surface.perfect
Not affected by velocity or surface area
Slope = coefficient of friction tells you about the type of surface
Errors:
One source of error is the fact that we could've taken data with more different weights. This would allow us to see how the affect of normal force would affect force of friction over more weight instead of having to extrapolate data. This would allow for a more accurate graph and less variability in slope. The second error was that we only did one experiment on each side. We could do the experiment again, this time adding more weights and seeing if the data from the previous experiment still holds true with the data of the second time we do the experiment. This, too, would allow for a more accurate reading of the experiments.
Journal Statement:
I feel I am becoming better at writing lab reports because I am able to remember what things are needed to include in the reports. I am able to write verbal and math models more easily and even more so, help my lab partners with theirs because it helps with the collective understanding of the lab report format. excellent - they too said you were helpful :) I could improve my writing by getting back critiques on even the most minute mistakes because I want to perfect my lab reports and in the same way be able to write lab reports without having to look at previous lab reports as reference. great job!
