Coefficient of static friction and minimum horizontal force

In summary, the coefficient of static friction is a dimensionless quantity that represents the maximum amount of friction between two surfaces before they begin to move relative to each other. It is calculated by dividing the maximum frictional force by the normal force, and can be affected by factors such as the nature of the surfaces, surface roughness, and the presence of lubricants or adhesives. The minimum horizontal force required to overcome static friction is directly related to the coefficient, which can be greater than 1 in some cases but is typically less than 1.
  • #1
kamalpreet122
13
0

Homework Statement



A 5.0 kg mass is held against a wall with which it has a coefficient of static friction of 0.85. What is the minimum horizontal force required to hold the mass against the wall ?

The teacher said answer is 58 N .. i can't get to that answer..

Homework Equations



Ff = UFn

The Attempt at a Solution



Ff = 0.85(49)
Ff = 41.65

this answer makes sense but for some reason ..the teacher has given us a different answer :S
 
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  • #2


Fnis the unknown.

Ff must be equal to the weight.
 
  • #3


yea that makes a lot of sense thanxx a lot :D
 

FAQ: Coefficient of static friction and minimum horizontal force

1. What is the coefficient of static friction?

The coefficient of static friction is a dimensionless quantity that represents the maximum amount of friction between two surfaces before they begin to move relative to each other. It is denoted by the symbol μs.

2. How is the coefficient of static friction calculated?

The coefficient of static friction is calculated by dividing the maximum frictional force that can exist between two surfaces without causing movement by the normal force between the two surfaces. Mathematically, it can be represented as μs = Fs max / N, where Fs max is the maximum frictional force and N is the normal force.

3. What factors affect the coefficient of static friction?

The coefficient of static friction is affected by several factors such as the nature of the two surfaces in contact, surface roughness, and the presence of any lubricants or adhesives. It also depends on the weight or normal force exerted on the surfaces and the angle at which the force is applied.

4. What is the significance of the minimum horizontal force in relation to the coefficient of static friction?

The minimum horizontal force is the minimum amount of force that needs to be applied horizontally to overcome the static friction and cause the two surfaces to start moving relative to each other. It is directly related to the coefficient of static friction and can be calculated by multiplying the coefficient by the normal force.

5. Can the coefficient of static friction be greater than 1?

Yes, the coefficient of static friction can be greater than 1. This typically occurs when two rough surfaces are in contact or when there is a significant amount of adhesion between the surfaces. However, in most cases, the coefficient of static friction is less than 1.

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