Coefficient of Kinetic friction and Friction force help Thanks

In summary, the conversation is about solving a typical "Ramp being pulled up an incline" question. The question involves finding the friction force and coefficient of kinetic friction. The equations used are Δk - ΔUgravity / distance for friction force and µk*n for coefficient of kinetic friction. There is also a clarification about the normal force equation, which is n = mg cos(30).
  • #1
nukeman
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Homework Statement



Im working on some typical "Ramp being pulled up an incline" questions and have trouble understanding something.

An example question where it stats a box is being pulled up a ramp like the image below:

Image: http://i43.tinypic.com/jb486q.jpg

Now, first: In order to find the friction force exerted on the box.

Would I simply just apply this: Δk - ΔUgravity / distance ?

AND...To find the coefficient of Kinetic friction, do I just go:

First find the normal force? which would be: n -mg cos 30 = 0, solve for n, which is 42.2N

THEN, just use this formula? ; fk = µk n ?



Homework Equations





The Attempt at a Solution

 
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  • #2
Isn't n = mg cos(30) ?
Yes, Ff = µk*n and Ff = Δk - ΔUgravity / distance
 

What is the coefficient of kinetic friction?

The coefficient of kinetic friction is a measure of the amount of friction between two surfaces in contact when there is relative motion between them. It is represented by the symbol μk.

How is the coefficient of kinetic friction calculated?

The coefficient of kinetic friction is calculated by dividing the force of kinetic friction (Fk) by the normal force (N) between the two surfaces: μk = Fk/N.

What factors affect the coefficient of kinetic friction?

The coefficient of kinetic friction is affected by the nature of the surfaces in contact (materials, roughness, etc.), the force pushing the surfaces together (normal force), and the presence of any lubricants or contaminants between the surfaces.

What is the significance of the coefficient of kinetic friction?

The coefficient of kinetic friction is important in understanding and predicting the behavior of objects in motion, such as the amount of force required to move an object across a surface or the stopping distance of a moving object.

How is the friction force related to the coefficient of kinetic friction?

The friction force (Fk) is directly proportional to the coefficient of kinetic friction. This means that the higher the coefficient of kinetic friction, the greater the friction force between two surfaces.

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