Static friction that wasn't a maximum

In summary: And think in each case, is the applied force equal to the maximum possible friction force? In most cases, it is not. In summary, static friction is not always at its maximum. It is only at its maximum when the applied force exceeds the maximum possible friction force between two surfaces. In most cases, the applied force is less than the maximum, allowing an object to remain stationary without sliding. Examples of this include standing on a ramp without sliding and pushing an object with a force less than the maximum friction force.
  • #1
Khemkhajon
12
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1. Describe a situation where you were dealing with static friction that wasn't a maximum
Im getting stuck on this question. Cause i can't think of a situation please some help would be appreciated
 
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  • #2
Also can someone not just tell answer but explain please.
 
  • #3
Can you tell me very simply what you understand by static friction?
 
  • #4
I thought static friction was always at its maximum, because I know That static friction force must be overcome by an applied force before an object will move. The maximum possible friction force between two surfaces before sliding begins is the product of the coefficient of static friction
so I am super stuck

she says its not a trick question
 
  • #5
Suppose there is a book on your table. You push it gently and horizontally with force F1, but it does not move. That means your force F1 is canceled by frictional force F1 acting in opp dircn. Again you push with force F2>F1, but still it does not move, meaning that the force of friction has now increased to F2 and canceled your applied force.

Like this if you keep on increasing, there will be some maximum force F_max, at which point the frictional force is not able to resist your push anymore. That is the maximum force of static friction. At that point, F_max = kN, where k is the co-eff of static friction. At all other times, when the applied force F is less than F_max, then F < kN.

Now you give some example.
 
  • #6
Shooting star said:
Suppose there is a book on your table. You push it gently and horizontally with force F1, but it does not move. That means your force F1 is canceled by frictional force F1 acting in opp dircn. Again you push with force F2>F1, but still it does not move, meaning that the force of friction has now increased to F2 and canceled your applied force.

Like this if you keep on increasing, there will be some maximum force F_max, at which point the frictional force is not able to resist your push anymore. That is the maximum force of static friction. At that point, F_max = kN, where k is the co-eff of static friction. At all other times, when the applied force F is less than F_max, then F < kN.

Now you give some example.

o ok so like if I pull a rock and doesn't move but keep increasing my force of pull it will overcome the maxium force of static friction. but I am confused sort of because max friction must be overcome. but i that example arent we just increasing our force to overcome the max friction. Isnt the question asking when is static friction not at its maximum.
 
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  • #7
You have been asked to give examples where the force of static friction is less than the maximum. As long as two surfaces in contact are stationary wrt each other, most probably the frictional force is less than maximum. The maximum represents a limiting case. As soon as the applied force exceeds the maximum, things start to slide relative to each other, and then kinetic friction takes over.

Suppose there's a ball rolling down an incline without slipping. As long as it’s not slipping, the frictional force is less than max. If a ladder rests against a wall, and you are climbing up, the friction is less than maximum up to a certain point. At the maximum, the ladder will just begin to slide.
 
  • #8
Khemkhajon said:
1. Describe a situation where you were dealing with static friction that wasn't a maximum



Im getting stuck on this question. Cause i can't think of a situation please some help would be appreciated

Have you ever stood on a ramp and not slid down it? How about a roof?

CS
 
  • #9
Khemkhajon said:
1. Describe a situation where you were dealing with static friction that wasn't a maximum



Im getting stuck on this question. Cause i can't think of a situation please some help would be appreciated

static friction is at a min. when the force applyed is less then the Fs,max. an example of this is if you try to push a object wirh a Fs,max of 5000000N and you apply a force of 9810N you don't have Fs,max you have a lesser force becouse friction can't be greater then the froce it is oposing
 
  • #10
Khemkhajon said:
Isnt the question asking when is static friction not at its maximum.

Let me repeat that in almost all cases where static friction is involved, it is less than the maximum.

Just think randomly of a few cases where static friction is involved. Like the examples stewartcs gave.
 

FAQ: Static friction that wasn't a maximum

1. What is static friction that wasn't a maximum?

Static friction that wasn't a maximum is a type of friction that occurs between two surfaces that are not in motion relative to each other, but the friction force is not at its maximum value. This means that the force required to overcome the friction and initiate motion is less than the maximum possible friction force between the two surfaces.

2. What causes static friction that isn't a maximum?

Static friction that isn't a maximum is caused by the roughness and imperfections of the surfaces in contact. These imperfections create microscopic hills and valleys, which interlock when the surfaces are pressed together, resulting in a greater friction force. However, if the surfaces are not pressed together with enough force, some of the hills and valleys may not interlock, resulting in a lower friction force.

3. Can static friction that isn't a maximum be greater than the maximum static friction?

No, static friction that isn't a maximum can never be greater than the maximum static friction. The maximum static friction is the maximum amount of force that can be applied to overcome the friction and initiate motion. If the force required to overcome the friction is less than the maximum static friction, then the static friction is not at its maximum value.

4. How is static friction that isn't a maximum different from kinetic friction?

Static friction that isn't a maximum and kinetic friction are two different types of friction forces. Static friction occurs when two surfaces are not in motion relative to each other, while kinetic friction occurs when two surfaces are sliding past each other. Additionally, the value of static friction can vary between zero and the maximum value, while the value of kinetic friction remains constant once the surfaces are in motion.

5. How does the coefficient of static friction affect static friction that isn't a maximum?

The coefficient of static friction is a measurement of the roughness and stickiness of the surfaces in contact. A higher coefficient of static friction means that the surfaces are more rough and have a greater tendency to stick together, resulting in a higher maximum static friction and a higher likelihood of static friction not being at its maximum value. However, the exact relationship between the coefficient of static friction and static friction that isn't a maximum is complex and can vary depending on the specific surfaces and conditions.

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