Simple coefficient of friction question

AI Thread Summary
The discussion focuses on calculating the coefficient of friction for a motor shaft under specific conditions. The user provides details including no load and loaded torque, surface area, mass, and rotational speed. They derive the resistive force from the difference between loaded and no load rotational forces. The coefficient of friction is calculated as 0.0428, which the user believes is realistic given the materials involved. Confirmation and further insights on the calculation are sought from the forum.
jmart157
Messages
20
Reaction score
0
Here's my givens... i need to find the coefficient of friction on the material.

No load torque on motor - 3.19 Nm
Loaded torque on motor - 3.49 Nm
Surface area in contact with motor shaft - .1885"
Mass of loaded material on shaft - 17.16 lbs = 76.33 N
Rads/sec - 31.42Looking to find the coefficient of friction. I need formulas and assistance please, not answers :)

Also, if I need to get/provide more information, I believe I can.

Jon
 
Last edited:
Physics news on Phys.org
alright, this came too easy. please confirm...

torque = Radius x force

which means rotational force = torque/radius

loaded rotational force = 41.83/2" = 20.92 lbsf
no load rotational force = 38.25/2" = 19.123 lbsf

resistive force from load = 20.92 lbsf - 19.123 lbs f = 1.7928 lbs

coefficient friction is (resistive force divided by rotational force) divided by 2

CoF = (1.7928/20.92)/2 = 0.0428

This seems realistic as this is plastic wearing against polished steel, in hot water. What do you guys think?
 

Thread 'Average velocity as a weighted mean'

Hello everyone, Consider the problem in which a car is told to travel at 30 km/h for L kilometers and then at 60 km/h for another L kilometers. Next, you are asked to determine the average speed. My question is: although we know that the average speed in this case is the harmonic mean of the two speeds, is it also possible to state that the average speed over this 2L-kilometer stretch can be obtained as a weighted average of the two speeds? Best regards, DaTario
View full post »

Thread '1:1 versus 2:1 Mechanical Advantage debate'

The rope is tied into the person (the load of 200 pounds) and the rope goes up from the person to a fixed pulley and back down to his hands. He hauls the rope to suspend himself in the air. What is the mechanical advantage of the system? The person will indeed only have to lift half of his body weight (roughly 100 pounds) because he now lessened the load by that same amount. This APPEARS to be a 2:1 because he can hold himself with half the force, but my question is: is that mechanical...
View full post »
Thread 'Beam on an inclined plane'

Thread 'Beam on an inclined plane'

Hello! I have a question regarding a beam on an inclined plane. I was considering a beam resting on two supports attached to an inclined plane. I was almost sure that the lower support must be more loaded. My imagination about this problem is shown in the picture below. Here is how I wrote the condition of equilibrium forces: $$ \begin{cases} F_{g\parallel}=F_{t1}+F_{t2}, \\ F_{g\perp}=F_{r1}+F_{r2} \end{cases}. $$ On the other hand...
View full post »

Similar threads

I Will This Friction Clamp Hold the Weight?
Replies
10
Views
2K
Coefficient of friction of various materials not listed in standard references
Replies
7
Views
4K
B Questions about momentum and force as well as normal force/friction
Replies
35
Views
3K
Question Regarding Coefficient of Friction
Replies
1
Views
2K
Wheel calculations (Power, torque, etc.)
Replies
4
Views
3K
Question regarding coefficient of static friction
Replies
10
Views
3K
Coefficient of friction question
Replies
12
Views
2K
What is Friction? Definition & Explanation
Replies
1
Views
2K
Torque calculations: Rotating vertical shaft
Replies
5
Views
5K
Coefficient of friction of a sandwiched body
Replies
15
Views
805

Hot Threads

Recent Insights

Back
Top