Maximum coefficient of friction physics problem

In summary: If there is a net force, then the the coefficient will be less than one.In summary, the maximum coefficient of friction is 1 because it is defined as a value between 0 and 1, with 0 representing no friction and 1 representing the maximum possible friction. This value is determined by the surfaces in contact and the angle of the ramp, and can be greater than 1 in some cases such as with glue or extremely rough surfaces. However, for most practical applications, the coefficient of friction is less than 1 due to the micro hills on surfaces limiting the steepness of the hills and thus the friction coefficient.
  • #1
ferranvalles
4
0
Can someone explain why the maximum coefficient of friction is 1??

Why μ <= 1 ?

Thank You.
 
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  • #2
I don't know I thought it could be greater than one . . . :confused:
 
  • #3
It could be greater then 1. For example if you have glue, or a really viscose m aterial between the two surface.
 
  • #4
314159271828 said:
It could be greater then 1. For example if you have glue, or a really viscose m aterial between the two surface.

But if you are talking about glues and something like this, you are not talking about friction, it's a different force.

For definition, when the coefficient of friction is m:

0<=m<=1

And I wonder, why m<=1?
 
  • #5
ferranvalles said:
But if you are talking about glues and something like this, you are not talking about friction, it's a different force.

For definition, when the coefficient of friction is m:

0<=m<=1

And I wonder, why m<=1?

Are you sure this isn't the elastic coefficient you're mixing it up with?
 
  • #6
No, the coefficient of friction does not need to be less than one. For two surfaces glued together, for example, the coefficient of friction would be infinite.

You may be confused by the fact that most of the surfaces you will be doing calculations for will have coefficients of friction less than one. This is simply because, in those cases, we are more interested in surfaces that slide relatively well against each other.
 
  • #7
You don't need glue. I recently attended a horse pulling contest where the winning team weighed about 3600 lb and pulled about 3900 lb. That's a coefficient of kinetic (yes, their hooves were slipping a little) friction of 1.08. Some other candidates for high coefficients might be a cheese grater, no 40 sandpaper, a file, stainless steel on aluminum, etc.
 
  • #8
Thank you everybody.

Now I understand the coefficient friction can be higher than 1.

Another explication is that in a ramp, the coefficient of friction is equal to the tangent of ramp's angle.

The angle can be higher than 45º, so the tangent would be also higher than 1, as a consequence we can get a coefficient as high as we want (considering that a body is holded in the ramp).
 
  • #9
Top Fuel drag car tires are getting a coefficient of friction well over 4.5. Table Tennis rubber is probably the stickiest, take a look at this video:

ttstick.wmv
 
  • #10
When talking about friction, never refer to glues or something like that. Glues adhere by different force,not friction.
I agree that most of the friction coefficients are lower than 1. There is reason for that. If you magnify the two surfaces of the table and let say an iron bar, these surfaces are not smooth but made of many micro hills (which you can see in an SEM picture of a metal). The steeper the hills (triangles), the higher the friction coefficient. If the steepness is 45 degrees, probably the coe. is 1. For many materials, the hill should not be steeper than 45 degrees, that the reason why coeficients are mainly lower than 1. Anyway, there are exceptional cases.
 
  • #11
ferranvalles said:
Thank you everybody.

Now I understand the coefficient friction can be higher than 1.

Another explication is that in a ramp, the coefficient of friction is equal to the tangent of ramp's angle.

The angle can be higher than 45º, so the tangent would be also higher than 1, as a consequence we can get a coefficient as high as we want (considering that a body is holded in the ramp).

That's only going to be the case if the Net force is 0 of an object on a ramp.
 

What is the maximum coefficient of friction?

The maximum coefficient of friction is the maximum amount of friction that can be generated between two surfaces in contact with each other.

How is the maximum coefficient of friction calculated?

The maximum coefficient of friction is calculated by dividing the maximum force of friction by the normal force. This can be represented by the equation μmax = Fmax / Fn.

What factors affect the maximum coefficient of friction?

The maximum coefficient of friction can be affected by several factors, including the types of surfaces in contact, the roughness of the surfaces, and the presence of any lubricants.

What are some real-world applications of the maximum coefficient of friction?

The maximum coefficient of friction is an important concept in engineering, as it helps to determine the maximum amount of force that can be applied to a structure before it begins to slip or slide. It is also used in designing brakes for vehicles and determining the safety of different types of flooring.

How does the maximum coefficient of friction differ from the coefficient of static friction?

The maximum coefficient of friction is the upper limit of the coefficient of friction, while the coefficient of static friction is the actual value of friction between two surfaces at rest. The maximum coefficient of friction is always higher than the coefficient of static friction, as it takes into account the force required to overcome static friction and initiate motion.

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