# Factor of friction strange behavior

• Achileas7
In summary, the speaker is conducting an experiment to measure the factor of friction between two different metals. When using steel and brass surfaces, the factor of friction decreases as the applied force increases. However, when using steel and aluminum surfaces, the factor of friction increases with an increase in applied force. The speaker is seeking an explanation for this phenomenon and assures that there are no measurement mistakes. The experimental setup involves a steel rotation disk, aluminum and brass rods, and a high standard rectifier machine. The coefficient of friction is measured using an electronic device and the formula μ=T/(2*F).
Achileas7
Hello everyone, I have a really interesting question here. I am measuring the factor of friction between two different metals. My results are a beat cloudy. When I use Steel - Brass surfaces the factor of friction, μ is being reduced while I am increasing the applied force. In other side, when I use Steel - Aluminum surfaces, when I am increasing the applied force on the two materials the factor of friction, μ goes up. Anyone can explain what is happening? There is no measurement mistake, that' s guaranteed.

Achileas7 said:
Hello everyone, I have a really interesting question here. I am measuring the factor of friction between two different metals. My results are a beat cloudy. When I use Steel - Brass surfaces the factor of friction, μ is being reduced while I am increasing the applied force. In other side, when I use Steel - Aluminum surfaces, when I am increasing the applied force on the two materials the factor of friction, μ goes up. Anyone can explain what is happening? There is no measurement mistake, that' s guaranteed.

You'll have to tell us a bit more: What are the magnitudes and ranges of normal forces that you're working with, how are the friction surfaces prepared, what pressure is involved, how is the normal force applied and how is the coefficient of friction measured? There are a lot of ways that your experimental setup could deviate from the ideal conditions in which the coefficient of friction is close to independent of the normal force.

(Also "no measurement mistake, that's guaranteed" is something that we've all regretted saying at least once. Just sayin' )

Nugatory said:
(Also "no measurement mistake, that's guaranteed" is something that we've all regretted saying at least once. Just sayin' )

One of our lab tutor told as so as, we aren' t supposed to focus on such a thing and focus on what' s going on I can understand you objections on that.

Now with the experiment part:
Our experimental setup includes a steel rotation disk, and to measure the friction factor we use some aluminum and brass rods of the same radius. We use pressures of 1, 2 and 3 bars which creates forces of about 106 N, 212 N and 318 N in our experimental setup.
The surfaces are being threw a high standard rectifier machine, which makes them really smooth. The forces are vertically applied on the rod. The coefficient of friction is measured by a electronical device which gives as the force of the friction. We use the type μ=T/(2*F) as we used two rods at the time, at the opposite side of the disk.

F: Applied Force
T: Friction Force
μ: Friction Factor

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## 1. What is friction and why is it important?

Friction is a force that resists the relative motion between two surfaces that are in contact. It is important because it helps objects stay in place, allows us to walk without slipping, and helps in the functioning of machines and engines.

## 2. How does the factor of friction affect the behavior of objects?

The factor of friction can greatly impact the behavior of objects. If the friction is high, it can cause objects to move slower or not at all. On the other hand, low friction can make objects move faster and with less resistance.

## 3. What are some common factors that can affect the friction between two surfaces?

Some common factors that can affect friction include the type of surface, the weight and shape of the object, and the presence of any lubricants or contaminants. Temperature can also play a role in friction, as it can affect the smoothness of surfaces.

## 4. Why does friction sometimes behave strangely or unpredictably?

Friction can behave strangely or unpredictably due to a phenomenon called stick-slip motion. This occurs when the friction between two surfaces causes them to alternate between sticking and slipping, resulting in jerky or inconsistent movement.

## 5. How can scientists measure and study the factor of friction?

Scientists use various methods to measure and study friction, such as using a friction force sensor, tribometers, or calculating the coefficient of friction. They also conduct experiments by changing different variables, such as surface materials or weight, to observe how friction is affected.

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