About circular Friction measurement

In summary: Thanks for the reply! In summary, the coefficient of rolling friction for rubber on tarmac (or asphalt) is 1.08.
  • #1
Jonh Doe
8
0
I need some information about the coefficient of circular or rolling friction for rubber on tarmac (or asphalt). It is to do a measurement of the force required to move an object of certain weight at regular speed on wheels.

I know that rolling friction is about 1/100 of the kinetic friction coefficient, and that this coefficient for rubber on tarmac is around 1.08, but I need a more precise measurement, and don't have access to such information.

If you could tell me this coefficient, or where I could find a way to calculate it or a chart that has it, it would help me. By the way, I cannot do the measurement directly, since the weight to move is around 1000 kg, and I don't have the required instruments.

Also, I would need help in how to measure the drag of air on an boject, if you know how.

Thanks for your replies
 
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  • #2
Jonh Doe said:
I need some information about the coefficient of circular or rolling friction for rubber on tarmac (or asphalt). It is to do a measurement of the force required to move an object of certain weight at regular speed on wheels.

I know that rolling friction is about 1/100 of the kinetic friction coefficient, and that this coefficient for rubber on tarmac is around 1.08, but I need a more precise measurement, and don't have access to such information.

If you could tell me this coefficient, or where I could find a way to calculate it or a chart that has it, it would help me. By the way, I cannot do the measurement directly, since the weight to move is around 1000 kg, and I don't have the required instruments.

Also, I would need help in how to measure the drag of air on an boject, if you know how.

Thanks for your replies
im familiar to static and kinetic friction, what is rolling friction?
 
  • #3
Just as a suggestion, you might have a relatively easy way to make this measurement. You could construct a simple contraption using one of those suspension springs and a simple frame (of wood or whatever). Then you could pull the car (at some constant speed, say 2 mph) and mark the stretched length of the spring on the frame. This together with the spring constant should give you 2 sig figs worth of determination. This may not work very well if the spring constant is too low or too high. The force you measure will be the rolling friction and the axle friction (not to be confused with each other). To get just the rolling friction of the tires, you could have them roll down a slight incline and record the time, but the deformation of the tires under the weight of the car would be absent, so I'm not sure this would be very accurate.
 
  • #4
In college, I think we called it the coefficient of rolling resistance, Cr, the fraction of the car's weight needed to maintain a constant velocity:

[tex]C_r=\frac{F}{W}[/tex]

To get a rough estimate, we used a bathroom scale that we pushed on to measure the force needed to keep the car rolling.
 
  • #5
Ah, that is much simpler and more available than my idea! :redface:

I don't know why I always try to make things so complicated.
 

1. What is circular friction measurement?

Circular friction measurement is a technique used to measure the friction between two surfaces that are in circular motion relative to each other. It is commonly used in engineering and materials science to evaluate the wear and tear of materials and the efficiency of lubricants.

2. How is circular friction measured?

Circular friction is typically measured using a tribometer, which is a specialized instrument that applies a rotational force to one surface while measuring the resulting frictional force. The data is then used to calculate the coefficient of friction, which is a measure of the resistance to motion between the two surfaces.

3. What factors can affect circular friction measurements?

Several factors can influence the accuracy of circular friction measurements, including the surface roughness and hardness of the materials, the temperature and humidity of the testing environment, and the speed and load applied to the surfaces. It is important to carefully control these variables to obtain reliable results.

4. What are the applications of circular friction measurement?

Circular friction measurement has a wide range of applications, including material testing, product development, and quality control in industries such as automotive, aerospace, and manufacturing. It is also used in research studies to better understand the behavior of different materials and lubricants under different conditions.

5. Are there any limitations to circular friction measurement?

While circular friction measurement is a valuable tool for evaluating surface properties, it does have some limitations. For instance, it may not accurately represent the friction between two surfaces in real-life applications due to the simplified testing conditions. Additionally, the results may vary depending on the specific testing method and equipment used.

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