Frictional Forces and Coefficients of Friction [Need help]

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SUMMARY

The discussion centers on calculating the minimum force required to keep a sled moving at a constant speed on a horizontal surface with a kinetic coefficient of friction of 0.20 and a mass of 2 slugs. The correct formula for frictional force is F(s) = μN, where μ is the coefficient of friction and N is the normal force. The normal force is calculated as N = mg, leading to F(s) = 0.20 * (2 slugs * 32 ft/s²), resulting in a frictional force of 12.8 pounds, not Newtons, as the user initially calculated.

PREREQUISITES
  • Understanding of frictional forces and coefficients of friction
  • Knowledge of mass and weight conversion (slugs to pounds)
  • Familiarity with basic physics equations involving force
  • Concept of normal force in physics
NEXT STEPS
  • Study the relationship between mass, weight, and gravitational force
  • Learn about the different units of force (pounds vs. Newtons)
  • Explore the implications of kinetic vs. static friction
  • Investigate real-world applications of friction in mechanical systems
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Students studying physics, particularly those focusing on mechanics and forces, as well as educators seeking to clarify concepts related to friction and force calculations.

tutojean
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Homework Statement


A sled is pulled at a constant speed over a horizontal surface where the kinetic coefficient of friction is .20. What is the minimum force necessary to keep the sled moving if its mass is 2 slugs?


Homework Equations



f(s)=U(s)N or f(s)=Ns(mg)

F(s)= Frictional Force
m=weight
g=gravity
(Not sure about this equation or problem)

The Attempt at a Solution



F(s) = Ns(mg)
F(s) = (.20)(2 slugs)(32 ft/s^(2))
F(s) = 12.8 N ?

Am I doing this right or wrong? Can somebody please show me how to do this?
 
Physics news on Phys.org
You did it right, except that the force units are not Newtons.

What force units go with feet, slugs, and seconds?
 

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