Uniform Circular Motion Problem

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SUMMARY

The discussion focuses on solving a uniform circular motion problem involving a banked curve designed for vehicles traveling at 93 km/h with a radius of 210 m. The correct angle of banking can be determined using the formula for centripetal acceleration, a = v²/r, which leads to the calculation of the banking angle. Additionally, if the curve is not banked, the minimum coefficient of friction required to prevent skidding is derived from the forces acting on the vehicle. The key equations involve centripetal force and the components of gravitational force acting on the vehicle.

PREREQUISITES
  • Understanding of centripetal acceleration and its formula, a = v²/r
  • Knowledge of forces acting on a vehicle in motion, including gravitational and normal forces
  • Familiarity with trigonometric functions, specifically sine and cosine
  • Basic principles of friction and its role in motion on inclined surfaces
NEXT STEPS
  • Calculate the banking angle using the formula θ = arctan(v²/(rg)) where g is the acceleration due to gravity.
  • Determine the minimum coefficient of friction using the equation μ = v²/(rg) for unbanked curves.
  • Explore the effects of different speeds on the banking angle and friction requirements.
  • Investigate real-world applications of banked curves in highway design and safety considerations.
USEFUL FOR

This discussion is beneficial for physics students, civil engineers, and anyone involved in transportation design, particularly those focusing on vehicle dynamics and road safety.

Gattz
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Homework Statement


A circular curve of highway is designed for traffic moving at 93 km/h. Assume the traffic consists of cars without negative lift. (a) If the radius of the curve is 210 m, what is the correct angle of banking of the road? (b) If the curve were not banked, what would be the minimum coefficient of friction between tires and road that would keep traffic from skidding out of the turn when traveling at 93 km/h?


Homework Equations



a=v2/r

The Attempt at a Solution


I found acceleration to be 3.177 m/s2. Then I tried setting ma to Fnradial, which I got to be mgcostheta * mgsintheta. But there are two thetas.
 
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Wheres the cosine coming from? I think the correct equation should be ma=mgsin(theta)
 
Before trying to directly calculate centripetal acceleration, ask yourself about the forces that act on a car in motion on a banked curve.
 

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