Physics Project Part 4 – Data Analysis and Conclusion

Data Analysis: 

Conclusion:

My original question: “On an inclined plane, what surface keeps an object completely still? Is the static coefficient of friction then comparable with online data?”, was answered during this experiment and I was able to find out which surface I used would be best to keep my desired object (phone with rubber case)  from sliding down while the surface is inclined. The “stickiest” surface was surprisingly metal, I initially believed that it would be wood because of its roughness. Metal was a smooth surface and I anticipated that it would have one of the fastest velocities, but this was not the case. Rubber and metal apparently have a high coefficient of friction between them causing the phone to go down it much slower. In the end I was able to dissect and see this, which answered my initial question; likewise, it was very interesting to see which surfaces had the greatest friction with the phone. Therefore, which surfaces were best suited to keep a phone with a rubber case from sliding off an inclined plane. Comparing the analyzed data to online sources produced its own conclusions. Metal had the highest coefficient of static friction with rubber by far and this was reliably proved true through the experiment. Equally, the aluminum whiteboard had one of the lowest coefficients of friction that was also showcased perfectly through the experiment. Altogether I was able to prove that this experiment was comparable with online data, legitimizing the experiment and its yield further. Overall, I was able to find the answer to my question, learn new things, practice inclined planes, and compare my findings with other sources; culminating in what I would call a success for both the experiment and my understanding of forces.

Sources of Uncertainty: 

  1. One source is reaction time when timing the objects descents. Unless mechanized it would be impossible to get perfectly accurate time data for this experiment. This could change the accuracy of velocity throughout the experiment.
  2. Another source of uncertainty is the curvature of the ramps. It would be unreasonable to assume that all the ramps had the same smoothness; this would slightly alter data.
  3. The accuracy of the measured angles would be another source of uncertainty. It is not reliable to assume that with a common protractor the exact angles needed can be found. This again would slightly alter data.
  4. Another source of uncertainty is online data. No matter how reliable the source,  the materials could be slightly different, which would compromise the comparison between my experiment and online data slightly.

Experiment Improvement: 

There are a few measures I would take to improve this experiment. I would invest and use better support/scaffolding to hold the ramps in place, so that they do not move as much. While the improvised support beams used during the experiment were useful and typically stable, having support that is actually meant for such a role would make the experiment much more legitimate. Another way I would improve this experiment would be to use ramp material that is more common; finding the static coefficient of friction for some ramps during this experiment online was a challenge and it would be much easier if the ramps used were made from ubiquitous materials like aluminum or steel. Finally, if I had another chance I would find a way to make timing the objects descent more reliable. The reaction time was a major source of uncertainty for this experiment and solving it would be a massive leap forward.

Unlimited Budget Improvements: 

There are many ways that a scientist with unlimited budget could theoretically improve my experiment. Firstly, they could invest in a mechanized system of timing, rigging the object to an apparatus so that as soon as it begins descent a timer begins. This would ensure that the accurate timing of the descent for this experiment. Unlimited budget would also assume that the ramps bought would have better curvature than the ones I had used, or at the very least the materials used would be high end. Better quality materials for the ramp would guarantee more reliable results; likewise, a higher budget would net better measuring materials to make measurements more legitimate as well.

Application of this Experiment: 

While it may sound initially unreasonable one application of my experiment is that now I have a better idea of what surfaces I can rest my phone atop at an angle. The surfaces with the least downwards velocity have been revealed to me through this experiment and it is reasonable to assume materials close to them in texture would preform the same. Knowing this, in everyday life I can pick and choose what surfaces are safest for my phone to rest on. Congruently, I know what surfaces have more friction compared to others and this can help me gauge the extent to which an object will rest upon them as their angles increase, it is general information that may be useful in everyday life.

 

 

Forces Project Part 3 – Data Collection

DISCLAIMER: All mention of acceleration should be replaced with velocity, it was incorrectly denoted as acceleration while it was actually velocity during the project.

Question: On an inclined plane, what surface keeps an object completely still? Is the static coefficient of friction then comparable with online data?

  • In general, the purpose of this experiment was to find what surface slowed my phone’s descent the most.
  • The ‘stickiest’ ramp was then used to find its maximum coefficient of friction that stopped the phones descent.
  • From there the purpose of the experiment is to find if this coefficient of friction is comparable with reliable online data.

Raw Data Collected:

Challenges/Problems Encountered:

  1. During data collection, it became difficult to both time and configure the desired set-up. Thankfully, this was solved when I got help from my fellow classmates, such as, Nathan.
  2. Having the ramps stay perfectly still was also a challenge. This was solved by using books, rulers, or stones to prop-up the lighter ramps and to stop them from moving.
  3. Another problem was that it was hard to accurately gauge acceleration because one single trial for each surface was far too unreliable. Doing multiple test trials and finding the average amongst them helped solve this problem and yield accurate acceleration.
  4. Many of the ramps began to slide forwards without any barrier to keep them sturdy. This was solved easily with a heavy textbook placed in front of the ramps, or a well placed ruler.

Updated FBD’s:

  • Since the changes to the procedure did not affect the FBD’s greatly, the only change to be made was a change to an original error with the FBD’s from the first project post. This error incorrectly showed the direction of Fnet in the FBD of the moving object.

FBD of object sliding down the inclined plane/ramp (corrected version).

 

Raw Data Reflection:

I would say that the raw data collected so far does seem reasonable and it was somewhat anticipated. Most surfaces I expected to fair poorly or well did just as I predicted. The raw data collected also is within the boundaries of the experiments likely magnitudes making me believe that it is once again reasonable. What surprised me was the ‘stickiest’ ramp surface and its acceleration. I did not anticipate metal to have high friction when in contact with the rubber of the phone. Its very low acceleration also made for surprise and interest. Overall, the raw data both seems reasonable and was generally the expected outcome for the experiment.

Experiment Images:

In this picture the use of books/other objects for sturdiness can be seen.

A picture showing the use of books, stones, among other objects, to prop-up the ramps.

A picture showing the angle at which the object stayed still on the ‘stickiest’ ramp.

Sources of Online Research: 

Whiteboard Coefficient of Static Friction 

Metal Coefficient of Static Friction 

Wood Coefficient of Static Friction

Cardboard Coefficient of Static Friction

 

Forces Project Planning Phase

Question: On an inclined plane, what surface keeps and object completely still? If the object is my phone and the surface is a wooden ramp, what force of friction would keep it from sliding down the ramp? Is the static coefficient of friction then comparable with online data?

  • For this question, the scenario includes finding what the coefficient of friction between the object and ramp is that results in the object staying at rest.
  • Solving this allows us to know on the surface the ramp is (wood, carboard, etc.)  what the coefficient of friction must be for the item, such as a phone, to remain still.
  • Solving this would also allow us to know if the coefficient of static friction found would be comparable at its maximum value with online resources.

Knowns/Constants:

  • The angle of the ramp must always be the same to keep data consistent. It can be changed later to find the maximum coefficient of friction for the object .
  • The material of the ramp can change to find the right coefficient of friction while the object must remain the same as we are testing to see what keeps it from sliding down.
  • We know that Fgx must equal Ff in order for the object to remain at rest, to get optimal Ff  we must find what the maximum requirement for the coefficient of friction is.
  • If we know what the coefficient of friction is based on research we can create an equation after Fgx is calculated to solve for Ff.
  • To find the magnitudes of variables needed in the force of friction equation, we must use vectors to solve the inclined plane.
  • After the phone (or other object) is weighed, using the angle of the ramp from the horizontal; the vectors of the inclined plane can be solved to show what Fgy and Fgx are.
  • After finding Fgy we know that FN will be equal to it.
  • We can use Fnet with acceleration in formulas to work towards the Ff and coefficient of friction if it is unknown.

Assumptions: 

  • It would be assumed that there is no air resistance at all on the object sliding down.
  • It would be assumed that the object slides down the ramp perfectly without any bumps.
  • It would be assumed that the forces are perfectly split among x and y axis’.
  • If found online, the coefficient of friction is applicable to the same material assumed that (there are no differences).
  • The descent of the object would be timed perfectly in m/s with a timer.

Experiment Planning:

  1. The data that needs to be collected for this experiment includes:
  • The force of gravity (weight) on the object.
  • The coefficient of friction (if it can be found online).
  • The angle at which the ramp is.
  • If the object continues to slide or if it stays still.
  • The normal force, Fgx, Fgy, and Ff would have to be collected using calculations of the measured variables.
  • How fast the object descends down the ramp.

2. Measuring Equipment that needs to be used:

  • A protractor to measure the angle of the ramp from the horizontal.
  • A scale or spring scales to measure the weight of gravity on the object.
  • A timer to time the descent of the object.
  • A meter stick to measure how far it goes down the ramp in m/s.
  • These tools, most likely, can be found at school

3. The Procedure followed will be:

  1. Gather 1 scale, a protractor, ramps each with a different surface (wood, cardboard etc.), and an object to slide down it (calculator, phone, etc.)
  2. Weigh the object and record its weight (force of gravity)
  3. Set up the ramp at a 45 degree angle from the horizontal floor or other flat surface.
  4. Set up a meter stick right along the ramp with the beginning at the top of the ramp where the object will start.
  5. Place the object on the ramp and record observations along with the time it takes for it to slide down, if it does at all.
  6. Change between surfaces and record observations, including how fast it slides down the ramp, if it does at all.
  7. Select the “stickiest” surface and find the angle at which the object remains at rest and solve for its coefficient of friction.
  8. Compare results of the solved inclined plane with online resources to determine if it is comparable and if it justifies the surface’s “stickiness”.

4. Websites that will possibly be used in research:

Coefficients of Friction for Common Materials

Coefficients of Friction: By the United Nations

  • This research will be used to find the coefficients of surfaces used to then compare them with the calculations made after the experiment.
  • This research will also be used to identify which surfaces are supposedly the “stickiest”.

Free Body Diagrams of Situation: 

Forces Project Ideas/Brainstorm

Suggestions:

Suggestion 1: Finding the coefficient of friction between a toy car and different surfaces, possibly with different lubricant on wheels, as it moves under constant motion.

  • The question would be to find the coefficient of friction for each case to find which is smallest while making predictions on combinations.
  • This would involve friction, weight, mass, normal force, constant velocity.
  • Assumptions made would be the lack of air resistance on the car, and perfect constant velocity when it is pushed.
  • I could get a toy car and different lubricants for its wheels.
  • I could alternate different surfaces and lubricants each time the car is rolled while calculating the coefficient of friction each time; then, I would find which surface and lubricant combination has the least friction.

Suggestion 2: How great does friction/inertia have to be an inclined surface to keep an object still against the weight.

  • The question would be to find how great friction has to be on a ramp to resist weight.
  • The assumptions made would be that the ramp is perfectly smooth and that the coefficient of static friction for the two surfaces is exact when found online or through calculation.
  • This would involve friction, weight, mass, normal force, and angles/inclined planes.
  • I could find the coefficient of friction between surfaces and calculate the normal force using a formula to see what the friction would be; then, I could test to see if it sticks to the surface better and slides down less.

Suggestion 3: How much does the weight of water droplets have to be for its surface tension to be broken?

  • The question here would be solved by finding the threshold within droplets still hang upside down and how much weight makes them fall.
  • The assumptions made here is that all the water droplets are identical and that the surface they stick to is uniform throughout.
  • This would involve surface tension, adhesion, the force of gravity, mass, and gravitational field strength between earth and the object.
  • I could find the mass of one water droplet and add them while calculating the force of gravity on the collective droplet each time more water is added to it; then I could possibly calculate its surface tension through a formula.

Brainstorm Ideas:

  • Something to do with friction
  • Friction while walking on a surface
  • Air resistance of basketball as it is shot into hoop
  • Coefficient of friction between toy cars with different lubricant/surfaces while they move under constant motion
  • How great does somethings inertia/friction have to be at an incline to resist the force of gravity on it downwards, as normal force does not keep it upright