Kinetic Friction and Incline for a Car

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SUMMARY

The discussion centers on the analysis of kinetic friction and incline forces acting on a car. The key equations include the friction force formula, f = μN, and the incline angle calculation, θ = arctan(1/10). The participant grapples with the direction of forces in the free body diagram (FBD), particularly the friction force acting in the positive x-direction as the car accelerates up the incline. This realization clarifies the role of friction as a driving force, opposing the weight's x-component, mgsinθ, which acts down the incline.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Familiarity with free body diagrams (FBD)
  • Knowledge of kinetic friction and its coefficient (μ)
  • Basic trigonometry for incline angle calculations
NEXT STEPS
  • Study the effects of varying incline angles on frictional forces
  • Explore the relationship between friction and acceleration in inclined planes
  • Learn about the role of normal force in different scenarios
  • Investigate real-world applications of friction in automotive engineering
USEFUL FOR

Students studying physics, particularly those focusing on mechanics, as well as automotive engineers and anyone interested in the dynamics of vehicles on inclines.

bartersnarter
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Homework Statement


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Homework Equations


friction:[/B] f = μN
incline angle: θ = arctan(1/10)
summation of forces in y: N - mgcosθ = 0
summation of forces in x: -f - mgsinθ = ma (?)

The Attempt at a Solution


For this problem, I set the x-axis going up the incline and the y-axis normal to said x-axis. When I drew the FBD, the part that did not make sense to me was the summation of forces in the x-axis. The question wants the car to accelerate UP the incline, but the two forces I draw for the FBD both point down the incline. One of the forces is the x-component of the weight, mgsinθ, and the other is the friction. I know the weight's x-component direction is right, so the wildcard is the friction. Isn't friction opposite to the direction of motion?
 
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I just had a thought... is friction the force which drives the car forward? The wheels spin in the negative x-direction (with respect to the ground) so the friction points to the positive x-direction. If that were the case it would make a lot of sense!
 

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