How Is Friction Force Calculated on an Incline?

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SUMMARY

The friction force on a 12kg mass on a 30-degree incline with a coefficient of static friction of 0.8 is calculated using the formula F = uN, where N is the normal force. The normal force is determined by the weight component acting perpendicular to the incline, calculated as Wcos(30). The correct friction force is 60 N, as the static friction force applies only when the object is about to slide. The gravitational force component acting down the incline must also be considered for accurate calculations.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Knowledge of static friction and its coefficient
  • Ability to calculate normal force on an incline
  • Familiarity with trigonometric functions, specifically cosine
NEXT STEPS
  • Study the derivation of the normal force on inclined planes
  • Learn about the differences between static and kinetic friction
  • Explore the application of Newton's second law in inclined plane problems
  • Investigate the role of angle in friction force calculations
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Students in physics, engineering professionals, and anyone interested in mechanics and friction calculations on inclined surfaces.

lu6cifer
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1.Quick question: a 12kg mass is on a 30 degree incline where the coefficient of static friction is 0.8. What is the friction force exerted on the mass?



2. F = ma, f = uN



3. I got around 83 N for this. All I did was multiply the coefficient of friction by normal force, which was Wcos30 in this case. So, 0.8 * 12 * 9.81 * cos30, giving me around 83 N, but my answer sheet says 60 N...
 
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Remember, the static friction force is equal to uN only when the object is about to slide relative to the surface. Is it? What is the component of the gravity force acting on the object down the plane?
 

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