Kinetic Friction and Newtons 2nd Law

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SUMMARY

The discussion focuses on calculating the power produced by a car engine under the influence of kinetic friction and drag force, specifically for a car weighing 15,000N with a drag force of 1,200N traveling at 30m/s. The coefficient of kinetic friction is established at 0.2. The analysis includes determining the additional force required when the car ascends a 10-degree incline and calculating the power needed to overcome friction on that incline. The participant emphasizes the distinction between static and kinetic friction in the context of the problem.

PREREQUISITES
  • Understanding of Newton's Second Law (F = ma)
  • Knowledge of kinetic friction and its coefficient (0.2)
  • Familiarity with drag force calculations
  • Basic principles of power calculation in physics
NEXT STEPS
  • Calculate the power output of the engine using the formula P = F × v
  • Explore the effects of incline on force and power requirements
  • Investigate the role of static vs. kinetic friction in vehicle dynamics
  • Learn about the impact of drag force on vehicle performance at constant speed
USEFUL FOR

Physics students, automotive engineers, and anyone interested in the dynamics of vehicle motion and power calculations in real-world scenarios.

larryboi7
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Homework Statement


A car weighing 15000N experiences a drag force of 1200N. The car travels 30m/s on a level highway. The coefficient of kinetic friction is 0.2. If the car travels for 10s at this speed, calculate the power the engine produces.

The car then goes up a 10 degree constant incline. Calculate the additional force the engine must now provide. Find the power for friction on the incline.


Homework Equations


F = ma
MkFn
a= v/t


The Attempt at a Solution


so far i got that 15000= mg m = 1529.1
a = 3m/s^2
 
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I find the wording of this problem bothersome, since there is no kinetic friction involved unless the non-driving wheels are locked and skidding (the driving wheels are what propels the car forward, due to static friction, which does no work). Beyond that , the car is NOT accelerating...it is moving at constant speed. The driving force on the level surface is just the force necessary to overcome drag...and whatever kinetic friction force may be acting, if the non-driving wheels are locked.
 

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