Coefficient of Static Friction on a Turntable

AI Thread Summary
The lab aims to determine the coefficient of static friction between a metal washer and both metal and rubber surfaces by measuring the RPM at which washers fly off a turntable at varying distances from the center. Data indicates that the coefficient of static friction is lowest at medium distances for both surfaces, with the highest coefficient for the rubber surface occurring at the shortest radius and for the metal surface at the largest radius. The participant seeks clarification on these unexpected results, particularly why the coefficients behave differently across distances. They express uncertainty about their methodology and request assistance in understanding the findings. The discussion highlights the complexities of friction coefficients in dynamic systems.
jhawks8
Messages
9
Reaction score
0
I'm doing a lab for my technical dynamics class and that lab is to determine the coefficient of static friction between a metal washer and both metal and rubber surfaces.

I did the experiment using 3 washers set at different distances from the center of the turntable as instructed, and recorded the RPM at which the washers of each distances flew off the turntable. My data is below:

Rubber Surface
r(m) |RPM |w(rad) |µ | AVG µ
0.03 |123 |12.88 |0.507|
0.03 |154 |16.13 | 0.796| 0.676
0.03 |147 |15.39 |0.724|

0.06 |100 |10.47 |0.671
0.06 |97 |10.16 |0.631 |0.607
0.06 |88 |9.22 |0.52

0.1 |71 |7.44 |0.564
0.1 |80 |8.38 |0.716 |0.647
0.1 |77 |8.06 |0.662

Metal Surface

r(m)|RPM |w(rad) |u...|AVG µ
0.06 |77 |8.06 |0.397
0.06 |67 |7.02 |0.301 |0.376
0.06 |80 |8.38 |0.43

0.08 |62 |6.49 |0.344
0.08 |62 |6.49 |0.344 |0.363
0.08 |67 |7.02 |0.402

0.1 |61 |6.39 |0.416
0.1 |61 |6.39 |0.416 |0.403
0.1 |58 |6.07 |0.376

What is not making sense to me is why the coefficient of static friction is the lowest when in the medium distances. Also, the largest coefficient for the metal surface is the largest radius, and the largest coefficient for the rubber surface is the shortest radius.

I need help understanding this, or if I'm doing something wrong and I don't know it. Any help is really appreciated.
 
Physics news on Phys.org
Sorry for the sloppy tables.
 
Thread 'Is 'Velocity of Transport' a Recognized Term in English Mechanics Literature?'
Here are two fragments from Banach's monograph in Mechanics I have never seen the term <<velocity of transport>> in English texts. Actually I have never seen this term being named somehow in English. This term has a name in Russian books. I looked through the original Banach's text in Polish and there is a Polish name for this term. It is a little bit surprising that the Polish name differs from the Russian one and also differs from this English translation. My question is: Is there...
I know that mass does not affect the acceleration in a simple pendulum undergoing SHM, but how does the mass on the spring that makes up the elastic pendulum affect its acceleration? Certainly, there must be a change due to the displacement from equilibrium caused by each differing mass? I am talking about finding the acceleration at a specific time on each trial with different masses and comparing them. How would they compare and why?
Back
Top