Coefficient of friction formulas help

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Homework Help Overview

The problem involves a sled being pulled across a sidewalk, focusing on the coefficient of sliding friction between the sled and the surface. The context includes forces acting on the sled and the conditions of motion.

Discussion Character

  • Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between the applied force and the frictional force, questioning the conditions of motion (constant speed vs. acceleration) and the appropriate formulas to use.

Discussion Status

Some participants have offered formulas and reasoning related to the forces involved, while others have pointed out discrepancies in the interpretation of motion, leading to further exploration of the concepts involved.

Contextual Notes

There is a focus on the assumption that the sidewalk is horizontal and the sled is moving at a constant speed, which influences the analysis of forces and friction.

Kdawg
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A 52-N sled is pulled across a cement sidewalk at a constant speed. A horizontal force of 36 N is exerted. What is the coefficient of sliding friction between the sidewalk and the metal runners of the sled?
What formulas would I use in this problem?
 
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Kdawg said:
A 52-N sled is pulled across a cement sidewalk at a constant speed. A horizontal force of 36 N is exerted. What is the coefficient of sliding friction between the sidewalk and the metal runners of the sled?
What formulas would I use in this problem?


It is simple !
Use the formula,
[tex]F = {\mu}_s * N[/tex]
where F is the horizontal force and N is the normal force, which is equal to the weight of the sled. (I assume that the cement sidewalk is placed horizontally).
 
Last edited:
Notice that the body is moving with uniform accelaration.
This means that the net force acting on the body is 0.
Therefore, [tex]\mu * 52 N = 36 N[/tex]
This gives, [tex]\mu = 36 / 52[/tex]
 
The body is moving with uniform *velocity*, not acceleration, otherwise the net force on the body would not be zero.
 

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